Electronically controlled timepiece, and power supply control method and time correction method therefor

ABSTRACT

An electronically controlled timepiece includes an analog circuit ( 160 ) driven by a power source ( 22 ), a logic circuit ( 170 ) driven by a constant voltage regulator circuit ( 161 ) forming part of the analog circuit, an oscillator circuit ( 51 ) driven by the constant voltage regulator, a power source switch ( 162 ) for cutting off the supply of power to the analog circuit other than the constant voltage regulator circuit from the power source during a time correction operation, and a clock cutoff gate ( 171 ) for cutting off a clock input from the oscillator circuit to the logic circuit. During the time correction operation, power consumption is reduced because only the oscillator circuit and the constant voltage regulator circuit are operative. The oscillator circuit is not suspended, and an error in time display is eliminated.

TECHNICAL FIELD

The present invention relates to an electronically controlled timepiecethat controls timepiece hand driving in response to a signal, as areference, from an oscillator circuit that employs a time standardsource such as a crystal oscillator, a power supply control method forthe electronically controlled timepiece and a time correction method forthe electronically controlled timepiece.

BACKGROUND ART

In one of known electronically controlled mechanical timepieces that arecontrolled by making use of an IC or a crystal oscillator, a generatorconverts, into electrical energy, mechanical energy released by amainspring, the electrical energy drives a rotation controller, whichcontrols a current flowing through a coil of the generator, and handssecured to train wheels that transmit the mechanical energy from themainspring to the generator are accurately driven to indicate accuratetime.

Electrical energy from the generator is once stored in a smoothingcapacitor, and the power from the capacitor drives the rotationcontroller. Since the capacitor is supplied with an alternating-currentelectromotive force in synchronization with the rotation period of thegenerator, it is not necessary to store power for a long period of timeto enable the rotation controller having an IC or a crystal oscillatorto operate. Conventionally, a relatively small capacitance capacitorenabling the IC or the crystal oscillator to operate for severalseconds, i.e., a capacitor of 10 μF or so is employed.

The electronically controlled mechanical timepiece needs no motorbecause the mainspring is a power source for driving timepiece hands,and is low cost with a small component count. It is sufficient if asmall amount of electrical energy needed to drive an electrical circuitis generated. A small input energy is enough to drive the timepiece.

The electronically controlled mechanical timepiece has the followingdrawback. When a time correction operation (a timepiece hand settingoperation) is performed with the crown pulled out, each of an hour hand,a minute hand, and a second hand is stopped to set an accurate time. Thestop of the hands stops train wheels, and thus the generator as well.

The input of the electromotive force to the smoothing capacitor from thegenerator is suspended, while the IC is continuously driven. The chargestored in the capacitor is discharged to the IC side, and a voltageacross terminals of the IC gradually drops. The voltage applied to theIC thus drops below an oscillation stop voltage (Vstop, for instance,0.6 V), leading to the stop of the rotation controller.

When the oscillation of the IC stops, the power consumption is reduced,and the voltage drop rate in the capacitor also becomes slow. When thetime correction operation takes time long enough to cause the voltage ofthe capacitor to drop below the oscillation stop voltage, the capacitortypically falls to a voltage of 0.3 to 0.4 V slightly lower than theoscillation stop voltage. When the time correction operation (handsetting time) becomes excessively long, to several minutes, forinstance, the capacitor is fully discharged with the voltage thereofdropped to zero V.

Even if the generator starts rotating with the crown pushed into afterthe hand setting, the capacitor, the voltage of which has once droppedbelow the oscillation stop voltage as a result of discharge, takes timebefore the capacitor is charged again to be high enough to reach a drivestart voltage (voltage capable of driving the IC) for the rotationcontroller. The IC (an oscillator circuit) remains inoperativethroughout, and no accurate time control is performed.

Specifically, when the crown is pulled out to a second step (for a handsetting mode) from a zero step (for a normal hand driving mode) or froma first step (for a calendar correction mode) at time point A as shownin FIG. 26, the rotor of the generator stops, stopping charging acapacitor C1. On the other hand, the capacitor C1 continuously feedselectrical energy to the rotation controller (including a “drive IC” ina drive circuit for driving the crystal oscillator as a time standardsource), thereby allowing the crystal oscillator to continuouslyoscillate.

The voltage of the power source capacitor C1 gradually drops. At timepoint B1 (within three minutes from time A, for instance), the handsetting operation ends, and the crown is pushed in, moving from thesecond step to the first step or zero step (for the normal operation).The generator becomes operative again, restarting the charging of thepower source capacitor C1, and raising the voltage of the power sourcecapacitor C1. In this case, the oscillation of the crystal oscillatorcontinuously oscillates, the drive circuit (the rotation controller)quickly resumes rotation control of the rotor (brake control), and anindication error subsequent to the hand setting becomes zero.

When the hand setting operation is prolonged to be longer than threeminutes, for instance, the voltage of the capacitor C1 drops below theoscillation stop voltage (Vstop, 0.6 V, for instance) of the drivecircuit, and the oscillation stops at time B2 at the moment the handsetting operation ends. Even if the crown is moved to the first step atpoint B2, the rotation controller takes the sum of time T1 and time T2before it resumes rotation control of the rotor, leading to anindication error.

The time T1 is a duration of time, during which the power sourcecapacitor C1 is charged to a voltage (Vstart) on which the drive circuitand the oscillator circuit in the rotation controller normally operate.The voltage Vstart is typically higher than the voltage Vstop, and is0.7 V, for instance.

The time T2 is a duration of time from the application of theoscillation start voltage (Vstart) until the oscillator circuit startsoscillating. The time T2 becomes longer as the voltage of the powersource capacitor C1 is lower, and ranges from several seconds to severalminutes, as shown in FIG. 27. For instance, when the oscillation startvoltage (Vstart=0.7 V) is reached with the power source capacitor C1gradually charged, the time T2 is approximately 20 seconds with thevoltage (0.7 V) applied thereto.

When the hand setting operation takes time, the voltage of the powersource capacitor C1 drops, thereby stopping the oscillation. Subsequentto the end of the hand setting operation, the oscillator circuit takestime T1+T2 before the start of the oscillation. Because of a lowervoltage applied thereto, the oscillator circuit takes several seconds toseveral minutes for T2 alone. Before the start of the oscillation, therotation of the rotor is not controlled. The hands gain or lose time,suffering from a substantial indication error.

The use of a large capacitance capacitor C1 to permit a longer handsetting time is contemplated. The oscillator circuit is thus preventedfrom stopping even if the hand setting takes three minutes or longer.

The use of a large capacitance capacitor slows the rise rate of thepower source voltage. When the mainspring is released and stopped, ittakes a long time to increase the voltage across the capacitor from thestate in which no charge is stored in the power source capacitor. For along time from the start of tightening of the mainspring to the rise ofthe power source voltage, the hands remain unable to present accuratetime. In this case, there is a possibility that the user may mistake thestate for a timepiece failure. Increasing the capacitance of thecapacitor is thus not practical.

Increasing the power generation capacity of the generator to completecharging in a short time is contemplated. This arrangement increases thesize of the generator, and also needs to increase the size of themainspring as the torque to be transferred from the mainspring forfeeding mechanical energy to the generator increases. This arrangementcannot be adopted for use in wristwatches, which are subject to thelimitation of area and thickness dimensions.

In some of a variety of electronically controlled timepieces, such as aself-winding generator timepiece, a solar-cell charging timepiece, abattery driven timepiece, other than the electronically controlledmechanical timepiece, an oscillator circuit or an IC is stopped during atime correction operation to reduce power consumption and to prolongoperation time. In this case, it takes several seconds to severalminutes for the oscillator circuit to stably operate. A time error isalso introduced.

It is an object of the present invention to provide an electronicallycontrolled timepiece, a power supply control method for theelectronically controlled timepiece, and a time correction method forthe electronically controlled timepiece.

DISCLOSURE OF THE INVENTION

An electronically controlled timepiece of the present invention whichincludes a power source, an analog circuit driven by the power source, apower supply circuit for a logic circuit arranged in the analog circuit,the logic circuit driven by the output of the power supply circuittherefor, and an oscillator circuit driven by the output of the powersupply circuit for the logic circuit. The electronically controlledtimepiece further includes a power source switch for suspending thesupply of electrical energy to the analog circuit other than the powersupply circuit for the logic circuit from the power source during a timecorrection operation of the electronically controlled timepiece, andclock input limiting means for suspending a clock input from theoscillator circuit to the logic circuit during the time correctionoperation.

In accordance with the present invention, the power source switchsuspends the supply of electrical energy from the power source, such asa capacitor or a battery, to the analog circuit other than the powersupply circuit for the logic circuit during the time correctionoperation (hand setting operation), and the clock limiting meanssuspends the clock input from the oscillator circuit to the logiccircuit. During the hand setting operation, only both the oscillatorcircuit and the power supply circuit for the logic circuit required todrive the oscillator circuit are driven with the remaining circuits allinoperative. With this arrangement, power consumption during the handsetting operation is reduced. When the capacitance of the capacitor issmall, the voltage drop in the power source capacitor is limited duringa typical hand setting operation (for instance, 3 to 5 minutes), and thedriving of the oscillator circuit is continuously performed. With theoscillator circuit continuously operating during the hand settingoperation, a normal control operation is quickly resumed after the handsetting operation, and the indication error at the shifting back fromthe hand setting operation is eliminated. With the power consumptionreduced, there is no need for a large-sized generator, and the presentinvention is implemented in a wristwatch, which is typically subject tothe limitation of area and thickness dimensions.

The power supply circuit for the logic circuit employs a constantvoltage regulator.

The electronically controlled timepiece preferably includes logiccircuit initializing means for initializing the internal status of thelogic circuit during the time correction operation (hand settingoperation).

If control information prior to the hand setting operation remains inthe logic circuit, governing control of a rotor is not smoothlyperformed at the shifting back from the hand setting operation, and thetime taken before the start of the governing control may be included asan error. In contrast, if the internal status of the logic circuit isinitialized when the clock input to the logic circuit is cut off at thehand setting operation, the governing control of the rotor at theshifting back from the hand setting operation is smoothly performed, andthe time indication error is reliably eliminated.

An electronically controlled timepiece preferably includes an externalcontrol member for setting two-step statuses of a normal mode and a timecorrection mode, and an external control member detector circuit fordetecting the status of the external control member, wherein theexternal control member detector circuit includes first and secondinverters, a first signal line for connecting the output of the firstinverter to the input of the second inverter, a second signal line forconnecting the output of the second inverter to the input of the firstinverter, and a selection switch for connecting a signal input line toone of the first and second signal lines with the external controlmember in the time correction mode, and for connecting the signal inputline to the other of the first and second signal lines with the externalcontrol member in the other mode.

A crown detector circuit 100 shown in FIG. 28 has typically been used todetect the pulled status of the external control member such as a crownor a button. For instance, the pulled statuses of the crown of theelectronically controlled mechanical timepiece include a normal zerostep (in which the mainspring is tightened by turning the crown with thehands turning and the generator generating), a first step (in which acalendar is corrected by turning the crown with the hands turning andthe generator generating), and a second step (in which time correctionis performed by turning the crown with the rotor stopping moving, thehands motionless, and the generator not generating).

The crown detector circuit 100 includes a switch 101 which is turned onand off depending on the pulled status of the crown, two pull-downresistors 102 and 103, and an inverter 104. The gate of the pull-downresistor 102 is at a voltage VDD (high level), and the pull-downresistor 102 is normally turned on. The gate of the pull-down resistor103 is connected to the pull-down resistor 102 through the inverter 104.The switch 101 is turned off (open) with the crown in the zero step orthe first step, and is turned on with the crown in the second step(closed). When the switch 101 is turned off with the crown in the zerostep or the first step, the pull-down resistor 102 is turned on, avoltage VSS, namely, a low-level signal is input to the inverter 104,and the output signal of the inverter 104 is transitioned to ahigh-level signal. The pull-down resistor 103 receives, at the gatethereof, the high-level signal, thereby turning itself on.

When the switch 101 is turned on with the crown in the second step, thevoltage VDD, namely, a high-level signal is input to the inverter 104,and the output of the inverter 104 is transitioned to a low-levelsignal. As described above, depending on the pulled status of the crown,the crown detector circuit 100 alternates between a “high-level”, signaland a “low-level” signal.in the output thereof, thereby detecting theposition of the crown.

In the conventional crown detector circuit 100, the pull-down resistor102 is turned on with the crown in the second step, and the pull-downresistor 102 consumes energy. Instead of the crown, a dedicated buttonis occasionally employed to set the hands. When the hands are set usingthe external control member, such as the crown or the button, anexternal control member detector circuit for detecting the status of theexternal control member has the same construction as that of the crowndetector circuit 100, and thus suffers from the same problem.

In contrast, the electronically controlled timepiece having theabove-described external control member detector circuit employing thelogic circuit almost eliminates energy consumption by the externalcontrol member, and therefore substantially reduces power consumptionduring the hand setting operation.

An electronically controlled timepiece of the present inventionpreferably includes a mechanical energy source, a generator which isdriven by the mechanical energy source, and generates an electromotiveforce, thereby supplying electrical energy, and a rotation controller,driven by the electrical energy, for controlling the rotation period ofthe generator.

In the electronically controlled timepiece, the capacitance of thecapacitor as the power source is small. The power consumption for thehand setting operation is reduced with the present inventionimplemented, the time required for the hand setting operation isassured, and the ease of use is attained.

A power supply control method for an electronically controlled timepieceof the present invention, which includes a power source, an analogcircuit driven by the power source, a power supply circuit for a logiccircuit arranged in the analog circuit, the logic circuit driven by theoutput of the power supply circuit therefor, and an oscillator circuitdriven by the output of the power supply circuit for the logic circuit,includes the step of suspending the supply of electrical energy to theanalog circuit other than the power supply circuit for the logic circuitfrom the power source during a time correction operation of theelectronically controlled timepiece, and the step of suspending a clockinput from the oscillator circuit to the logic circuit during the timecorrection operation.

In accordance with the present invention, during the time correctionoperation of the electronically controlled timepiece, the supply ofelectrical energy to the analog circuit other than the power supplycircuit for the logic circuit from the power source such as a capacitoror a battery is suspended, and the clock input from the oscillatorcircuit to the logic circuit is suspended. The power consumption duringthe hand setting operation is reduced. Even with a small capacitancecapacitor, the voltage drop in the power source capacitor is limitedduring a typical hand setting operation (for instance, 3 to 5 minutes),and the driving of the oscillator circuit is continuously performed. Atthe shifting back from the hand setting operation, a normal controloperation is quickly resumed after the hand setting operation, and thetime indication error at the shifting back from the hand settingoperation is eliminated.

During the hand setting operation of the electronically controlledtimepiece, the internal status of the logic circuit is preferablyinitialized. If the internal status of the logic circuit is initializedwhen the clock input to the logic circuit is cut off at the hand settingoperation, the governing control of the rotor at the shifting back fromthe hand setting operation is smoothly performed, and the timeindication error is reliably eliminated.

An electronically controlled timepiece of the present invention, whichincludes a mechanical energy source, a generator, driven by themechanical energy source, for outputting electrical energy, a storageunit for storing electrical energy output by the generator, and arotation controller, driven by electrical energy supplied by the storageunit, for controlling the rotation period of the generator, includes apower supply control unit for suspending the supply of electrical energyfrom the storage unit to the rotation controller while the generatorstops the operation thereof in response to the time correctionoperation, and an indication error corrector unit for correcting anerror in time indication until the rotation controller resumes a normaloperation, when the power supply control unit restarts the supply ofelectrical energy from the storage unit to the rotation controller inresponse to the operation of the generator.

In accordance with the present invention, the power supply control unitsuspends the supply of electrical energy from the storage unit to therotation controller when the generator stops the operation thereofduring the time correction operation (hand setting operation). Althoughthe oscillator circuit of the rotation controller stops operating, thestorage unit is maintained in a charged state during the suspension ofthe operation of the generator.

Even before the generator fully reaches the operation thereof at theshifting back from the hand setting operation, the storage unit feedselectrical energy to the rotation controller to cause the rotationcontroller to be fully operative. A time lag prior to the operation ofthe rotation controller is eliminated, and an error in the time controlat the hand setting operation is thus minimized. Since the voltage ofthe storage unit is maintained at a relatively high level, the timeprior to the start of the oscillator circuit of the rotation controlleris shortened, and the rotation controller is quickly set to beoperative.

With the indication error corrector unit incorporated, the indicationerror of the hand before the normal operation of the rotation controlleris corrected to the extent that the indication error is eliminated orminimized.

The indication error corrector unit may be designed to perform aconstant quantity correction corresponding to a predetermined value, ormay set a correction value in accordance with a voltage of the storageunit.

The indication error corrector unit may adjust a correction value bydetecting temperature.

Specifically, the indication error corrector unit may include atemperature sensor, a voltage detector for measuring a voltage of thestorage unit, and a correction value setter for setting a correctionvalue based on values detected by the temperature sensor and the voltagedetector.

Since the voltage of the storage unit is maintained at a certainmagnitude, the time, which the oscillator circuit, with a certainvoltage applied thereto, takes to start oscillation, is substantiallyconstant. By performing a constant quantity correction corresponding toa certain value, the indication error is sufficiently reduced. When acorrection value is adjusted by detecting the actual voltage of thestorage unit, a highly precise correction is performed to minimize theindication error.

The time prior to the start of the oscillation with the voltage appliedto the oscillator circuit varies with temperature as shown in FIG. 16.For this reason, the temperature sensor included in the electronicallycontrolled timepiece measures temperature in the vicinity of theoscillator circuit, and the correction value is adjusted in accordancewith the measured temperature. A more precise correction is thusperformed. The indication error, under high temperature conditions orlow temperature conditions, is thus further minimized.

The power supply control unit preferably includes a switch which isconnected in series with the storage unit and is closed while thegenerator is running, and is opened while the generator is not running.

An electrical switch is acceptable as the switch, but a mechanicallydriven switch is preferable. When the electrical switch is used, thesupply of power may be occasionally not completely blocked. In such acase, as well, a mere leakage current (1 nA) of a silicon diodeconstituting the electrical switch is discharged. The switch cutoffeffect of the switch is almost identical to that of the mechanicallydriven switch. The use of the mechanically driven switch is preferablefrom the standpoint of the fully cutting off the supply of power.

The switch is preferably a mechanically driven switch that is openedwhen a crown remains pulled out to a time correction (hand setting)mode, and is closed when the crown is pushed into to a normal mode. Withthe switch opened and closed in response to the operation of the crown,the switch is interlocked with the hand setting operation.

A second storage unit (a second capacitor) is preferably connected inparallel with the storage unit. With the second storage unit arranged,power is continuously fed by the second storage even if the timepiecesuffers from a mechanical shock, with the switch chattering. Thisarrangement prevents the rotation controller from being shut down by thechattering.

A time correction method for an electronically controlled timepiece,which includes a mechanical energy source, a generator, driven by themechanical energy source, for outputting electrical energy, a storageunit for storing electrical energy output by the generator, and arotation controller, driven by electrical energy supplied by the storageunit, for controlling the rotation period of the generator, includes thestep of suspending the supply of electrical energy from the storage unitto the rotation controller during a time correction operation of theelectronically controlled timepiece, and the step of correcting an errorin time indication until the rotation controller resumes a normaloperation when the supply of electrical energy from the storage unit tothe rotation controller is restarted at the end of the time correctionoperation.

At the end of the time correction operation, the indication error may becorrected by a constant quantity correction corresponding to apredetermined value or may be corrected by a correction value set inresponse to the voltage of the storage unit. At the end of the timecorrection operation, temperature may be detected, and the correctionvalue may be adjusted in accordance with the detected temperature.

In accordance with the present invention, the power supply control unitsuspends the supply of electrical energy from the storage unit to therotation controller when the generator stops the operation thereofduring the time correction operation. The storage unit is maintained ina charged state during the suspension of the operation of the generator.Immediately subsequent to the shifting back from the time correctionoperation, the storage unit feeds electrical energy to the rotationcontroller to cause the rotation controller to be operative. Since theapplied voltage is maintained at a relatively high level, the rotationcontroller is quickly set to be operative, and the indication errorsubsequent, to the time correction operation is reduced.

Furthermore, since the indication error is corrected in accordance withthe voltage value of the storage unit and temperature, the indicationerror of the hands prior to the normal operation of the rotationcontroller is corrected. The indication error is thus eliminated.

An electronically controlled timepiece of the present invention, whichincludes a mechanical energy source, a generator, driven by themechanical energy source, for outputting electrical energy, and arotation controller, driven by electrical energy, for controlling therotation period of the generator, includes a main storage unit forstoring electrical energy supplied by the generator to drive therotation controller, an auxiliary storage unit connected in parallelwith the main storage unit through a mechanically driven switch that isinterlocked with a time correction operation, and a charge controlcircuit, arranged between the main storage unit and the auxiliarystorage unit, for adjusting charging currents to the main storage unitand the auxiliary storage unit, and a direction and a magnitude of acurrent flowing between the main storage unit and the auxiliary storageunit.

The charge control circuit preferably makes the charging current (chargequantity) to the auxiliary storage unit smaller than the chargingcurrent (charge quantity) to the main storage unit when the mechanicallydriven switch is closed to charge the main storage unit and theauxiliary storage unit with electrical energy from the generator, andallows the auxiliary storage unit to charge the main storage unit whenthe voltage of the auxiliary storage unit is higher than the voltage ofthe main storage unit.

Since the present invention includes the auxiliary storage unit that isdisconnected from the main storage unit and the generator by themechanically driven switch, the auxiliary storage unit is maintained ina charged state even when the generator stops the operation thereofduring the time correction operation (hand setting operation) in themiddle of the normal hand driving. Even if the terminal voltage acrossthe main storage unit drops below the voltage capable of driving therotation controller at the shifting back from the hand settingoperation, a current flows from the auxiliary storage unit to the mainstorage unit with the mechanically controlled switch closed. With itsvoltage increased, the main storage unit drives the rotation controller,and a time lag prior to the operation of the rotation controller iseliminated, and an error in the time control at the hand settingoperation (an error in the time indication subsequent to the timecorrection operation) is thus minimized.

When the hand setting operation takes time, when the timepiece has beenleft unattended for a long period of time to the degree that theterminal voltage across the auxiliary storage unit drops as a result ofa self-discharge, the mechanically driven switch is closed to allow acurrent to flow from the generator to each storage unit. In this case,the charge control circuit for adjusting the direction and the magnitudeof the current makes the charging current to the main storage unitlarger than the charging current to the auxiliary storage unit, and themain storage unit is charged to be high enough to quickly drive therotation control circuit. Even after the timepiece has been leftunattended for a long period of time, the rotation controller is quicklydriven. An error due to a time lag prior to the start of the driving ofthe rotation controller is reduced, and an error in the time controlduring the hand setting operation is minimized.

The present invention thus assures both the startup capabilitysubsequent to the hand setting and the accuracy of the hand setting atthe same time.

Preferably, the charge control circuit composed of a passive elementonly is used to control the charging and discharging between the mainstorage unit and the auxiliary storage unit. The use of the chargecontrol circuit composed of the passive element reduces powerconsumption and the generation capacity of the generator, compared tothe arrangement in which a comparator, i.e., an active element, is used.

When the charging and discharging are controlled between the two storageunits (such as capacitors), i.e., the main storage unit and theauxiliary storage unit, the control of the charging and discharging ofthe capacitor is typically performed by detecting the voltage of eachcapacitor using a comparator, and by using the output of the comparatorto cause a switch circuit, composed of transistors, to operate. In sucha timepiece, the comparator is an active element, and the comparatorneeds power to detect the voltage. The power consumption thus increases.

In a system, such as this timepiece, in which the generation capacity isextremely small, the generation capacity of the generator needs to beincreased from a current level to supply power to the comparator. Toincrease the generation capacity of the generator, means for increasingtorque or increasing the size of the generator itself may becontemplated.

In the former means, increasing the energy supply from the mainspringallows the mainspring to fast release. The duration of time of thereleasing of the mainspring from the fully tightened position thereof isshortened. In the latter means, the size of the generator becomes large,presenting difficulty in the layout of components in a timepiece thathas a limited space available. As a result, the size of the timepieceitself is increased.

Since the present invention includes the charge control circuit havingthe passive element, the power consumption thereof is small, compared tothe arrangement in which the comparator, as an active element, isemployed. A generator having a small generation capacity thus works.

The capacitance of the main storage unit is preferably set to be equalto or lower than the capacitance of the auxiliary storage unit. Withthis arrangement, the voltage of the main storage unit is rapidlyincreased by allowing the current to f low from the auxiliary storageunit when the main storage unit is discharged. The drive circuit, drivenby the main storage unit, is also rapidly driven.

Preferably, the mechanically driven switch is opened during the timecorrection operation, and is closed at the end of the time correction.

With this arrangement, the auxiliary storage unit is reliably cut offfrom the rotation controller with the generator stopped during the timecorrection operation (hand setting operation), and the auxiliary storageunit keeps the charged state thereof for a long period of time, and along hand setting time is thus permitted.

The charge control circuit preferably includes a resistor and a diodeconnected in parallel with the resistor, wherein the diode is configuredwith the reverse direction thereof aligned with the direction of acurrent charging the auxiliary storage unit from the generator and theforward direction thereof aligned with the direction of a current of theauxiliary storage unit charging the main storage unit.

When the generator charges each storage unit in this arrangement, acurrent flows through the auxiliary storage unit via the resistorconnected in parallel with the diode. The charge quantity to the mainstorage unit and to the auxiliary storage unit is controlled by theresistance of the resistor. For instance, the use of a resistor having ahigh resistance as large as 100 MΩ allows less current to flow to theauxiliary storage unit and more current to flow to the main storageunit, thereby rapidly charging the main storage unit. By setting anappropriate resistance to the resistor, the charge quantity to the mainstorage unit is controlled.

At the time of the shifting back from the hand setting operation, thecharging of the main storage unit by the auxiliary storage unit isperformed through the diode with a small charging loss involved therein,compared to the charging performed through the resistor.

The charge control circuit may include a diode only having a reverseleakage current, and wherein the diode is configured with the reversedirection thereof aligned with the direction of a current charging theauxiliary storage unit from the generator and the forward directionthereof aligned with the direction of a current of the auxiliary storageunit charging the main storage unit.

With this arrangement, a small reverse leakage current of the diode isfed to the auxiliary storage unit when each storage unit is charged withthe generator. For this reason, less current flows to the auxiliarystorage unit, while more,current flows to the main storage unit.

At the time of shifting back from the hand setting operation, thecharging current from the auxiliary storage unit to the main storageunit is aligned with the forward direction of the diode, and the voltagedrop and charging loss therethrough are thus reduced.

Furthermore, if the charging control circuit is constructed of a diodeonly, the component count of the charging control circuit, and thus ofthe timepiece, becomes smaller, leading reduced manufacturing costs.

The charge control circuit may include a resistor and a one-way elementconnected in parallel with the resistor, wherein the one-way element isconfigured to cut off a current flowing in a direction to charge theauxiliary storage unit from the generator and to conduct a current ofthe auxiliary storage unit flowing in a direction to charge the mainstorage unit. In this case, the one-way element may be a diode having noreverse leakage current.

As in the charge control circuit constructed of the diode and theresistor in parallel connection, the generator charges each of thestorage units, and the auxiliary storage unit is charged through theresistor so that the charge quantity to the main storage unit is largefor rapid charging. When the auxiliary storage unit charges the mainstorage unit, the charging is performed through the one-way element, anda charging loss to the main storage unit is minimized.

When the one-way element, such as a diode having no reverse leakagecurrent, allowing currents flowing therethrough in one direction only,is used, an error in the charge quantity due to the reverse leakagecurrent is not created. The charging current is thus preciselycontrolled.

An electronically controlled timepiece preferably includes an indicationerror corrector unit for correcting an error in time indication untilthe rotation controller resumes a normal operation when the supply ofelectrical energy of the main storage unit to the rotation controller isrestarted with the mechanically driven switch closed.

With the indication error corrector unit incorporated, the timeindication error until the rotation controller resumes the normaloperation is corrected, and the indication error is eliminated orminimized.

In this case, again, the indication error corrector unit may be designedto perform a constant quantity correction corresponding to apredetermined value, or may set a correction value in accordance with avoltage of the storage unit. Furthermore, the indication error correctorunit may adjust a correction value by detecting temperature. Morespecifically, the indication error corrector unit may includes atemperature sensor, a voltage detector for measuring a voltage of thestorage unit, a correction value setter for setting a correction valuebased on values detected by the temperature sensor and the voltagedetector.

A power supply control method for an electronically controlled timepieceof the present invention which includes a mechanical energy source, agenerator, driven by the mechanical energy source, for outputtingelectrical energy, and a rotation controller, driven by electricalenergy, for controlling the rotation period of the generator, includesthe step of arranging a main storage unit which stores electrical energysupplied by the generator to drive the rotation controller andconnecting an auxiliary storage unit in parallel with the main storageunit through a mechanically driven switch, the step of opening themechanically controlled switch during a time correction operation of theelectronically controlled timepiece, and the step of flowing a currentfrom the auxiliary storage unit to the main storage unit to charge themain storage when the voltage of the auxiliary storage unit is higherthan the voltage of the main storage unit with the mechanically drivenswitch closed at the end of a time correction operation, and the step ofmaking a charging current supplied from the generator to the mainstorage unit greater than a charging current supplied from the generatorto the auxiliary storage unit when the voltage of the auxiliary storageunit is not higher than the voltage of the main storage unit.

In this arrangement as well, the main storage unit is charged to be highenough to quickly drive the rotation control circuit at the shiftingback from the hand setting operation and an error due to a time lagbefore the start of the driving of the rotation controller is reduced,and an error in the time control during the hand setting operation (anerror in the time indication subsequent to the time correctionoperation) is minimized.

Even after the timepiece has been left unattended for a long period oftime, the rotation controller is quickly driven. An error due to a timelag before the start of the driving of the rotation controller isreduced, and an error in the time control during the hand settingoperation is minimized. The present invention thus assures both thestartup capability subsequent to the hand setting and the accuracy ofthe hand setting at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the construction of an electronicallycontrolled timepiece of a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing the construction of a controlcircuit of the first embodiment.

FIG. 3 is a circuit diagram of a rotation controller of the firstembodiment.

FIG. 4 is a timing chart of the circuit of the first embodiment.

FIG. 5 is a timing chart of the circuit of the first embodiment.

FIG. 6 is a waveform diagram showing an alternating-current outputsignal of a generator in the circuit of the first embodiment.

FIG. 7 is a flow chart showing a control method of the first embodiment.

FIG. 8 is a flow chart showing a power supply control method of thefirst embodiment.

FIG. 9 is a flow chart showing a crown position detection process in thepower supply control method of the first embodiment.

FIG. 10 is a block diagram showing the construction of an electronicallycontrolled timepiece of a second embodiment of the present invention.

FIG. 11 is a circuit diagram showing the construction of a controlcircuit of the second embodiment.

FIG. 12 is a block diagram showing a power supply control unit of thesecond embodiment.

FIG. 13 is a block diagram showing an indication error corrector unit ofthe second embodiment.

FIG. 14 shows an initial value setting table in the indication errorcorrector unit.

FIG. 15 is a diagram showing variations in the voltage of a capacitorand the voltage applied to a drive circuit in the second embodiment.

FIG. 16 is a graph showing applied voltage versus oscillation start timecharacteristics of an oscillator circuit with temperature as aparameter.

FIG. 17 is a table listing inputs and outputs of an AID converter in theindication error corrector unit.

FIG. 18 is a block diagram showing the construction of an electronicallycontrolled timepiece of a third embodiment of the present invention.

FIG. 19 is a circuit diagram showing the construction of a power supplycircuit of the third embodiment of the present invention.

FIG. 20 is a diagram showing variations in the voltage of a capacitorand the voltage applied to a drive circuit in the third embodiment.

FIG. 21 is a diagram showing variations in the voltage of a capacitorand the voltage applied to a drive circuit in the third embodiment.

FIG. 22 is a circuit diagram showing the construction of a power supplycircuit of a fourth embodiment of the present invention.

FIG. 23 is a block diagram showing the construction of an electronicallycontrolled timepiece of a fifth embodiment of the present invention.

FIG. 24 is a circuit diagram showing the construction of a power supplycircuit of the fifth embodiment.

FIG. 25 is a circuit diagram showing an modification of the secondembodiment.

FIG. 26 is a diagram showing variations in the voltage of a capacitorand the voltage applied to a drive circuit a conventional art.

FIG. 27 is a graph showing applied voltage versus oscillation start timecharacteristics of an oscillator circuit.

FIG. 28 is a circuit diagram showing a conventional crown detectorcircuit.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, the embodiments of the present invention arenow discussed.

FIG. 1 is a block diagram showing the construction of an electronicallycontrolled mechanical timepiece that is an electronically controlledtimepiece of a first embodiment of the present invention.

The electronically controlled mechanical timepiece includes a mainspring1 a as a mechanical energy source, accelerating train wheels 7 asmechanical energy transmission means for transmitting torque of themainspring la to a generator 20, and a hand 13, as a time display unitfor indicating time, connected to the accelerating train wheels 7.

The generator 20 is driven by the mainspring 1 a via the acceleratingtrain wheels 7, and generates an electromotive force to supplyelectrical energy. The alternating-current output from the generator 20is rectified by a rectifier circuit 21, which has at least one of thefunctions of stepup and rectification, full-wave rectification,half-wave rectification, and transistor rectification, and is stepped upas required. The alternating-current voltage is then fed to a powersupply circuit 22 as a power source such as a capacitor to charge it.

Referring to FIG. 2, a brake circuit 120 is added to the generator 20 inthis embodiment. Specifically, the brake circuit 120 includes a switch121 which applies a brake by making a closed loop by shorting a firstalternating-current output terminal MG1 to which the alternating-currentsignal (alternating current) generated by the generator 20 is output,and a second alternating-current output terminal MG2. The brake circuit120 is assembled into the generator 20 which also works as a governor asshown in FIG. 1. The switch 121 includes an analog switch or asemiconductor switch (bilateral switch), etc, which may be opened andclosed in response to a chopping signal (chopping pulse) CH3

The stepup and rectifier circuit 21 (the rectifier circuit 21 in FIG. 1)includes a capacitor 123 for voltage stepup connected to the generator20, diodes 124 and 125, and the switch 121. The diodes 124 and 125 maybe of any one-way element that allows a current to flow in one way, andthe type thereof is not important. Since the electronically controlledmechanical timepiece, in particular, has a small electromotive-forcegenerator 20, a Schottky barrier diode having a small forward voltage Vfis preferred as the diode 125. A silicon diode with a reverse leakagecurrent thereof is preferred as the diode 124.

A direct-current signal, rectified by the rectifier circuit 21, chargesa capacitor (power supply circuit) 22.

The brake circuit 120 is controlled by a rotation controller 50, whichis an electronic circuit, driven by power supplied from the capacitor22. The rotation controller 50 includes an oscillator circuit 51, arotor rotation detector circuit 53, and a brake control circuit 56 asshown in FIG. 1 and FIG. 2.

The oscillator circuit 51 generates an oscillation signal (32768 Hz)using a crystal oscillator 51A, i.e., a time standard source, and theoscillation signal is divided into a constant period through a frequencydivider 52 having twelve stages of flipflops. An output Q12 at a twelfthstage of the frequency divider 52 is output as an 8-Hz reference signal.

The rotation detector circuit 53 includes a wave shaping circuit 61 anda monostable multivibrator 62, each connected to the generator 20. Thewave shaping circuit 61 is composed of an amplifier and a comparator,and converts a sine wave into a rectangular wave. The monostablemultivibrator 62 functions as a bandpass filter that passes pulseshaving a predetermined period or shorter, and outputs a rotationdetection signal FG1 with noise removed therefrom.

The control circuit 56 includes an up/down counter 54 as brake controlmeans, a synchronization circuit 70, and a chopping signal generator 80.

The up/down counter 54 respectively receives, at an up count input and adown count input thereof, the rotation detection signal FG1 of therotation detector circuit 53 and the reference signal fs from thefrequency divider 52, via the synchronization circuit 70.

The synchronization circuit 70 is composed of four flipflops 71 and anAND gate 72, and causes the rotation detection signal FG1 to synchronizewith the reference signal fs (8 Hz) using a fifth-stage output (1024 Hz)and a sixth-stage output (512 Qz) of the frequency divider 52. Thesynchronization circuit 70 outputs these signal pulses in a manner suchthat they are not concurrently output.

The up/down counter 54 is composed of a 4-bit counter. The up/downcounter 54 receives, at the up count input thereof, a signal based onthe rotation signal FG1 from the synchronization circuit 70, andreceives, at the down count input thereof, a signal based on thereference signal fs from the synchronization circuit 70. With thisarrangement, the up/down counter 54 concurrently counts the referencesignal fs, the rotation signal FG1 and the difference between the twocounts.

The up/down counter 54 is provided with four data input terminals(preset terminals) A through D. Terminals A, B and Dare supplied with ahigh-level signal, setting the initial value (preset value) of theup/down counter 54 to count “11”.

Connected to the load input of the up/down counter 54 is an initializingcircuit 91, which is connected to the capacitor 22, for outputting asystem reset signal SR when power is initially fed to the capacitor 22.The initializing circuit 91 outputs a high-level signal until thecharged voltage of the capacitor 22 reaches a predetermined voltage, andthen outputs a low-level signal when the predetermined voltage isreached.

The up/down counter 54 does not accept the up and down inputs until theload input, i.e., the system reset signal SR is transitioned to a lowlevel, and the up/down counter 54 is maintained at a count of “11”.

The up/down counter 54 is provided with 4-bit outputs QA-QD. The thirdand fourth bits QC and QD output a high-level signal when the count is“12” or higher, and at least one of the third and fourth bits QC and QDnecessarily outputs a low-level signal when the count is “11” or lower.

The output LBS of an AND gate 110, to which outputs QC and QD are input,is a high-level signal when the up/down counter 54 gives the count of“12” or higher, and is a low-level signal when the up/down counter 54gives the count of “11” or lower. The output LBS is connected to thechopping signal generator 80.

The outputs of a NAND gate 111 and an OR gate 112, each receiving theoutputs QA-QD, are input to each of the NAND gates 113, to which theoutputs of the synchronization circuit 70 are also input. When the upcount input signal is repeatedly input causing the count to reach “15”,the NAND gate 111 outputs a low-level signal. Then, if a further upcount input signal is input to the NAND gate 113, the input is canceled,and no further up count input signal afterward is input to the up/downcounter 54. Similarly, when the count reaches “0”, the OR gate 112outputs a low-level signal, and a further down count input signal iscanceled. In this way, the count is prevented from shifting “15” to “0”,or shifting from “0” to “15”.

The chopping signal generator 80 includes first chopping signalgenerating means 81, constructed of three AND gates 82-84, foroutputting a first chopping signal CH1 based on the outputs Q5-Q8 of thefrequency divider 52, second chopping signal generating means 85,constructed of two OR gates 86 and 87, for outputting a second choppingsignal CH2 based on the outputs Q5-Q8 of the frequency divider 52, anAND gate 88 for receiving the output LBS of the up/down counter 54 andthe output CH2 of the second chopping signal generating means 85, and aNOR gate 89 for receiving the output of the AND gate 88 and the outputCH1 of the first chopping signal generating means 81.

The output CH3 of the NOR gate 89 in the chopping signal generator 80 isinput to the gate of the switch 121 constructed of a P-channeltransistor. When the CH3 is a low-level signal, the switch 121 is keptturned on, shorting the generator 20 for braking.

When the CH3 is a high-level signal, the switch 121 is kept turned off,applying no brake on the generator 20. The chopping signal from theoutput CH3 thus controls the generator 20 in chopping control. Therotation controller 50, including the chopping signal generator 80outputting the chopping signal, opens or closes the switch 121 forchopping.

The rotation controller 50 is divided into an analog circuit 160 and alogic circuit 170 according to types as shown in FIG. 3. The analogcircuit 160 is driven by a power source VSS, and specifically includespart of the rotation detector circuit 53 that acquires information aboutthe rotational status of the rotor from the generator 20 and therectifier circuit 21, and a circuit for controlling the rectifiercircuit 21. The information about the rotational status of the rotor,acquired by the rotation detector circuit 53, is transferred to thelogic circuit 170.

The analog circuit 160 includes a constant voltage regulator 161 whichis a power supply circuit for the logic circuit. The constant voltageregulator 161 is driven by the power source VSS, and outputs a constantvoltage Vreg that is lower than the power source VSS. The constantvoltage regulator 161 works as a power source for driving all circuits(the oscillator circuit 51 and the logic circuit 170) other than therectifier circuit 21 and the analog circuit 160.

The logic circuit 170 includes a frequency divider and a variety ofcontrol circuits, and also includes the control circuit 56 that acquiresinformation about the rotational status of the rotor, chiefly, from theanalog circuit 160 to govern and control the generator 20 to rotate therotor at a constant speed.

Each of the rotation detector circuit 53 and the control circuit 56includes the analog circuit 160 and the logic circuit 170.

The electronically controlled timepiece further includes an crowndetector circuit 180, which is an external control member detectorcircuit for detecting the pulled position of the crown, which is anexternal control member for switching between the normal mode and thehand setting mode. In the electronically controlled timepiece, themainspring is ready to be tightened when the crown is turned. The crownis pulled in three steps, i.e., a zero step, a first step, and a secondstep. With the crown in the zero step, the timepiece is in a normalgenerating and hand driving state. With the crown in the first step, thetimepiece is in a normal generating and hand driving state with thecalendar ready to be corrected. With the crown in the third step, therotor stops rotation with neither hand driving nor power generationcarried out.

The crown detector circuit 180 includes a first signal line 183 forconnecting the output of a first inverter 181to the input of a secondinverter 182, a second signal line 184 for connecting the output of thesecond inverter 182 to the input of the first inverter 181, and aselection switch 186 which connects the second signal line 184 to asignal input line 185 of the crown that is connected to the power sourceVDD when the crown is in the hand setting mode (in the second step), andwhich connects the first signal line 183 to the signal input line 185when the crown is at another mode (in the zero step or the first step)other than the hand setting mode .

The first signal line 183 of the crown detector circuit 180 is connectedto a power cutoff switch 162, which is a switch for cutting off thesupply of electrical energy to the analog circuit 160, and a clockcutoff gate 171, which is clock input limiting means for cutting off theclock input to the logic circuit 170 from the oscillator circuit 51. Thefirst signal line 183 is further connected to a reset terminal of thelogic circuit 170. With a low-level signal input at the reset terminal,the internal status of the logic circuit 170 is reset to the initialstate thereof.

The power cutoff switch 162 remains on while the crown detector circuit180 provides a high-level output, and remains off while the crowndetector circuit 180 provides a low-level output. The clock cutoff gate171 is composed of an AND gate, and directly feeds a clock signal fromthe oscillator circuit 51 to the logic circuit 170 when the crowndetector circuit 180 provides a high-level output, and blocks the signalfrom the oscillator circuit 51 when the crown detector circuit 180provides a low-level signal.

The operation of the present embodiment in the hand driving mode isdiscussed, referring to timing charts shown in FIG. 4 through FIG. 6,and a flow chart shown in FIG. 7.

When the generator 20 starts operating, causing the initializing circuit91 to output a low-level system reset signal SR to the load input of theup/down counter 54 (Step 31, hereinafter simply referred to S ratherthan Step), the up count input signal based on the rotation signal FG1and the down count input signal based on the reference signal fs arecounted by the up/down counter 54 as shown in FIG. 4 (S32). Thesesignals are adjusted through the synchronization circuit 70 so that theyare not concurrently input to the up/down counter 54.

When the up count input signal is input with the initial count of “11”,the count is shifted to “12”. The output LBS is driven high, and isoutput to the AND gate 88 in the chopping signal generator 80.

When the down count input signal is input, causing the count to returnto “11”, the output LBS is driven low.

In the chopping signal generator 80, the first chopping signalgenerating means 81 gives the output CH1 and the second chopping signalgenerating means 85 gives the output CH2, based on the outputs Q5-Q8 ofthe frequency divider 52, as shown in FIG. 5.

When the up/down counter 54 outputs a low-level output LBS (with thecount at “11” or lower), the output of the AND gate 88 is also at a lowlevel. The output CH3 of the NOR gate 89 is a chopping signal, which isan inverted CH1, having a duty factor (the ratio of turn on time of theswitch 121) of a long high-level duration (brake off time) and a shortlow-level duration (brake on time). The brake on time of the referenceperiod becomes short, and practically, no brake is applied to thegenerator 20. Specifically, the weak brake control with a priorityplaced on power generation is performed (S33 and S35).

When the up/down counter 54 outputs a high-level output LBS (with thecount at “12” or higher), the output of the AND gate 88 is also at ahigh level. The output CH3 of the NOR gate 89 is a chopping signal,which is an inverted CH2, having a duty factor of a long low-levelduration (brake on time) and a short high-level duration (brake offtime). The brake on time of the reference period becomes long, andstrong brake control is performed to the generator 20. However, thebrake off is repeated at regular intervals, permitting the choppercontrol, in which a reduction in generated power is controlled whilebraking torque is increased (S33 and S34).

The stepup and rectifier circuit 21 stores charge generated by thegenerator 20 into the capacitor 22. Specifically, the polarity of afirst alternating-current terminal MG1 is “−” while the polarity of asecond alternating-current terminal MG2 is “+”, and the voltage inducedat the generator 20 charges a capacitor 123 having a capacitance of 0.1μF, for instance.

On the other hand, the polarity of the first alternating-currentterminal MG1 becomes “+” while the polarity of the secondalternating-current terminal MG2 becomes “−”, and the sum of the voltageinduced at the generator 20 and the charge voltage at the capacitor 123charges the capacitor 22.

At each of the above states, the generator 20 are shorted and thenopened between the terminals thereof by the chopping pulse, inducing ahigh voltage across the terminals of the coil as shown in FIG. 6. Thishigh charge current charges the power supply circuit (capacitor) 22,thereby increasing the charging efficiency.

When the torque of the mainspring 1 a is large enough to rotate thegenerator 20 at a high rotational speed, a further up count input signalmay be fed even after the up count signal raised the count to “12”. Insuch a case, the count rises to “13”, and the output LBS remains at ahigh level. The strong brake control is thus performed in which a brakeis applied while being turned off at regular intervals by the choppingsignal CH3. With a brake applied, the rotational speed of the generator20 drops. If the reference signal fs (the down count input signal) isinput twice before the entry of the rotation signal FG1, the count dropsto “12”, and to “11”. At the moment the count drops to “11”, weak brakecontrol is selected.

In such a brake control, the generator 20 reaches a set rotationalspeed, and the up count input signal and the down count input signal arealternately input to the up/down counter 54, causing the count toalternate between “12” and “11” in a locked state as shown in FIG. 4. Inresponse to the count, the strong brake control and weak brake controlalternate. Specifically, in one reference period during which the rotormakes one revolution, the chopping signal having a large duty factor andthe chopping signal having a small duty factor are fed to the switch 121to perform the chopping control.

The mainspring 1 a is unwound, outputting a smaller torque, and thebrake on time is gradually shortened. The rotational speed of thegenerator 20 becomes close to the reference speed even with no brakeapplied.

With no brake applied at all, the down count input signal is morefrequently input. The count drops to a value of “10” or smaller, and thetorque of the mainspring 1 a is regarded as lowered. The hand is thusmotionless or left moving at a very slow speed. A buzzer may be sounded,or a light may be lit to urge the user to tighten the mainspring 1 a.

While the up/down counter 54 outputs a high-level LBS signal, the strongbrake control is performed using the chopping signal having a large dutyfactor. While the up/down counter 54 outputs a low-level LBS signal, theweak brake control is performed using the chopping signal having a smallduty factor. Specifically, the up/down counter 54 as the brake controlmeans switches between the strong brake control and the weak brakecontrol.

In the embodiment, during the low-level LBS signal, the duty factor ofthe CH3 chopping signal is 15:1 (high-level duration:low-levelduration), namely, {fraction (1/16)}=0.0625. During the high-level LBSsignal, the duty factor of the CH3 chopping signal is 1:15 (high-levelduration:low-level duration), namely, {fraction (15/16)}=0.9375.

Referring to FIG. 6, the generator 20 outputs, across MG1 and MG2, analternating current in response to the change in magnetic flux.Depending on the output LBS signal, the chopping signals CH3 at aconstant frequency but different duty factors are fed to the switch 121.When the high-level LBS signal is output, namely, during the strongbrake control, the short-circuit braking time in each chopper cycle islengthened. The amount of braking increases, reducing the rotationalspeed of the generator 20. As the amount of breaking increases,generated power is reduced, accordingly. However, energy accumulatedduring the short-circuit braking is output when the chopping signalturns off the switch 121, and is used to step up the output voltage ofthe generator 20. In this way, a reduction in generated power during theshort-circuit braking is compensated for. The braking torque is thusincreased while the reduction in generated power is restricted.

When the low-level LBS signal is output, namely, during the weak brakecontrol, the braking time in the chopping cycle is shortened, increasingthe rotational speed of the generator 20. In this case, also, thechopping signal turns the switch 121 from on to off, and chopper voltagestepup results. The generated power is large compared with the generatedpower with no brake applied at all.

The alternating-current output of the generator 20 is stepped up andrectified through the voltage stepup and rectifier 21, and charges thepower supply circuit (capacitor) 22, which in turn drives the rotationcontroller 50.

The output LBS of the up/down counter 54 and the chopping signal CH3 arecommonly based on the outputs Q5-Q8 and Q12 of the frequency divider 52.More specifically, the frequency of the chopping signal CH3 is aninteger multiple of the frequency of the output LBS, and the change insignal level of the output LBS, namely, a switch timing between thestrong brake control and the weak brake control, takes place insynchronization with the chopping signal CH3.

Control of the time correction operation (hand setting operation) isperformed in this embodiment as discussed below.

When the crown is pulled out from the normal hand driving position forthe hand setting position, the control flow shown in FIG. 8 isperformed. Specifically, a storage register “pre_RYZ” for storingpreceding crown position data is initialized (the value 3 issubstituted) (S1). The value input at the initialization is any valueother than the values set for representing the positions of the crown.For instance, when the crown positions are represented by two values “0”and “1”, 2 or larger number is acceptable. When three values “0”, “1”,and “2” are used, “3” or larger number may be used.

The crown position is detected (S2). The detection of the crown positionis performed by the crown detector circuit 180 as described in thecontrol flow shown in FIG. 9.

When the crown is placed in the zero step or the first step, the switch186 is connected to the first signal line 183. Since the crown, namely,the switch 186 is connected to the power source VDD, a high-level signalis fed to the first signal line 183. This signal is inverted through thesecond inverter 182 and the first inverter 181 as in “high low-Thigh”,and the output of the crown detector circuit 180 remains high. Thestatus of the first signal line 183 is detected (S21), and adetermination is made of whether the status is a high-level signal(S22). A high-level signal determines that the crown is placed in thezero step or in the first step, and the value “1” is entered into thestorage register “now_RYZ” storing current crown position data (S23).

When the crown is placed in the second step, the switch 186 is connectedto the second signal line 184. The high-level signal from the powersource VDD is inverted by the first inverter 181 into a low-levelsignal, which becomes the output of the crown detector circuit 180.Since the low-level signal is inverted into a high-level signal by thesecond inverter 182, the output signal of the crown detector circuit 180remains low. The state of the first signal line 183 is detected (S21),and a determination is made of whether the state of the first signalline 183 is a high-level signal (S22). When the signal is found to benot high, namely, low, it is determined that the crown is placed in thesecond step, and the value “0” is entered to the storage register“now_RYZ” for the current crown position (S24).

Since the second signal line 184 is at a low level when the switch 186is turned, the high-level signal and the low-level signal are shorted,allowing a short-circuit current to flow and consuming energy in vain.In this embodiment, the resistances of the inverters 181 and 182 are setto be large, making the current flowing therethrough to be small, andthe short-circuit current taking place as a result of the short isminimized.

When the position of the crown is detected, a determination is made ofwhether pre_RYZ is larger than 1 (S3). When it is found that pre_RYZ isequal to or smaller than 1 (i.e., “0” or “1” as will be discussedlater), a determination is made of whether pre_RYZ is equal to now_RYZ,in other words, whether the preceding position of the crown and thecurrent position of the crown are the same (S4). If it is found that thepreceding position and the current position are the same, a power supplycontrol process to be discussed later is not necessary, and the controlflow returns to the detection process of the crown (S2).

When it is found that pre_RYZ is not equal to now_RYZ (S4), or when itis found that pre_RYZ is larger than 1, in other words, the crown ispulled out from the normal hand driving mode and remains initialized(S3), the current crown position data now_RYZ overwrites the precedingcrown position data pre_RYZ (S5).

A determination is made of whether new_RYZ is larger than “0” (S6) todetermine the current crown position.

When it is found that now_RYZ is larger than “0”, namely, is “1”, withthe crown placed in the zero step or the first step, the power cutoffswitch 162 is turned on, causing power from the power source VSS to besupplied to the analog circuit 160 (S7). The clock signal from theoscillator circuit 51 is directly fed to the logic circuit 170 (S8). Thenormal hand driving control is thus performed, and the power generationis maintained. If the logic circuit 170 remains initialized, that stateis released (S9).

On the other hand, when it is found that now_RYZ is “0”, i.e., the crownposition is in the second step, the power cutoff switch 162 is turnedoff, cutting off power from the power source VSS to the analog circuit160 (S10). The input of the clock signal from the oscillator circuit 51to the logic circuit 170 is also cut off (S11). When the output of thecrown detector circuit 180 is transitioned to an low-level signal, theinternal status of the logic circuit 170 is reset, and the logic circuit170 is initialized (S12).

However, the power supplying to the constant voltage regulator 161 ismaintained, and the oscillator circuit 51 driven by the constant voltageregulator 161 remains operative.

The control flow returns to the crown position detection step (S2), andthe above-discussed steps (S2 through S12) are repeated.

During the hand setting operation, a mechanical mechanism stops therotation of the rotor, the hands are not driven and power is notgenerated.

When the crown is pushed to the zero step or the first step subsequentto the hand setting operation, the crown detector circuit 180 outputs ahigh-level signal, closing the power cutoff switch 162, and therebydriving the analog circuit 160. Furthermore, the clock cutoff gate 171conveys the clock signal from the oscillator circuit 51. The initializedlogic circuit 170 performs governing control on the rotor.

This embodiment provides the following advantages.

1) During the hand setting operation with the rotor suspended and nopower generated, the power cutoff switch 162, as a power source switch,suspends the supply of power to the analog circuit 160. The clock cutoffgate 171, as clock limiting means, cuts off the clock input to the logiccircuit 170, completely stopping the operation of the timepiece. Thepower consumption of the timepiece is thus reduced.

With this arrangement, the voltage drop across the power supply circuit(capacitor) 22 is restricted, and for a duration of time for the handsetting operation (3 to 5 minutes, for instance), the oscillator circuit51 is continuously driven. When the crown is pushed in to resume powergeneration subsequent to the hand setting, the rotation controller 50becomes operative immediately after the generator 20 starts generatingin succession to the finish of the hand setting, because the oscillatorcircuit 51 has been continuously operated without any interruption.Unlike the conventional art, no time lag takes place before theoscillator circuit 51 becomes operative. No time indication error iscaused from the hand setting operation to the resumption of timemeasurement. An accurate hand setting operation is thus carried out.

2) Since the crown detector circuit 180, namely, an external controlmember detector circuit, is a logic circuit composed of the inverters181 and 182, the power consumption therethrough is reduced. The overallpower consumption is made even smaller. Time before a voltage reductiontakes place across the power supply circuit (capacitor) 22 is prolonged.The duration of time allowed for the hand setting operation is thusaccordingly prolonged.

3) Since the resistances of the inverters 181 and 182 are set to belarge to limit a short-circuit current, the power consumption throughthe crown detector circuit 180 is reduced more.

4) Since the logic circuit 170 is reset for initialization during thehand setting operation, control is usually started with the initialstate when the generator 20 resumes the operation thereof subsequent tothe finish of the hand setting operation. The governing control of therotor is smoothly performed, correct control state is quickly resumed,and the creation of a time indication error is reliably prevented.

5) The rectifier circuit 21 steps up voltage through chopping, inaddition to the voltage stepup through the use of the capacitor 123, thedirect-current output voltage of the rectifier circuit 21, namely, thecharge voltage of the capacitor 22 is thus increased.

A second embodiment of the present invention is now discussed, referringto FIG. 10 through FIG. 17. In this embodiment, components identical tothose described in connection with the preceding embodiment aredesignated with the same reference numerals and the discussionthereabout is omitted or briefly made.

Referring to FIG. 10, the electronically controlled mechanicaltimepiece, which is the electronically controlled timepiece of thisinvention, includes a mainspring 1 a as a mechanical energy source,accelerating train wheels (series of wheels) 7 as mechanical energytransmission means for transmitting torque of the mainspring 1 a to agenerator 20, and a hand 13, as a time display unit for indicating time,connected to the accelerating train wheels 7.

The generator 20 is driven by the mainspring 1 a via the acceleratingtrain wheels 7, and generates an electromotive force to supplyelectrical energy. The alternating-current output from the generator 20is rectified by a rectifier circuit 21, which has at least one of thefunctions of stepup and rectification, full-wave rectification,half-wave rectification, and transistor rectification, and is stepped upas required. The alternating-current voltage is then fed to a powersupply circuit 22 as a power source such as a capacitor to charge it.

The generator 20 is governed and controlled by the rotation controller50. The rotation controller 50 includes an oscillator circuit 51, arotor rotation detector circuit 53, and a brake control circuit 56, andthe construction thereof remains unchanged from that of the firstembodiment as shown in FIG. 11.

The oscillator circuit 51 generates an oscillation signal (32768 Hz)using a crystal oscillator 51A, a time standard source, and theoscillation signal is divided into a constant period through a frequencydivider and is output as a reference signal fs.

The rotation detector circuit 53 is composed of a wave shaping circuitconnected to the generator 20, and converts the alternating-currentoutput from the generator 20 into a rectangular wave, and outputs as arotation detection signal FG1 with noise removed therefrom.

The control circuit 56 compares the rotation detection signal FG1 withthe reference signal fs, thereby setting the amount of braking, andapplying a brake on the generator 20 to govern it.

Specifically, the rotation controller 50 includes a drive circuit 57composed of a drive IC for driving the oscillator circuit 51 as shown inFIG. 12. Like the constant voltage regulator 161 in the first embodimentshown in FIG. 3, the drive circuit 57 drives the oscillator circuit 51and the logic circuit. The drive circuit 57 is driven by power (powersource VSS) from the power source capacitor 22 as the power supplycircuit, and outputs a constant level voltage Vreg lower than the powersource VSS. A switch 261, which is a power supply control unit, controlsthe supply of power from the power source capacitor 22 to the drivecircuit 57.

In the electronically controlled timepiece of this embodiment, the crowncan be pulled out in three steps, wherein in a zero step, the mainspringis tightened by turning the crown with the hands turning and thegenerator generating, and in a first step, a calendar is corrected byturning the crown with the hands turning and the generator generating,and in a second step, time correction is performed by turning the crownwith the rotor stopping moving, the hands motionless, and the generatornot generating. The switch 261 is closed with the crown placed in thefirst or zero step, and is opened with the crown placed in the secondstep. In other words, the switch 261 is a mechanically driven switchthat operates in interlock with the time correction operation.

A switch 262 is connected to the drive circuit 57. The switch 262 is amechanically driven switch which operates in interlock with the switch261, and is used to input a crown position signal to the drive circuit57. Specifically, the switch 261 is closed with the crown placed in thezero or first position, and the switch 262 is connected to a zero andfirst step circuit in interlock with the switch 261. With the crownplaced in the second step, the switch 261 is opened, and the switch 262is connected to a second step circuit. Recognizing the signal from thesecircuits, the drive circuit 57 performs timepiece control, for instance,performing normal hand driving control with the crown in the zero orfirst step, and setting or resetting a counter and system initializationwith the crown in the second step.

A second capacitor 25, connected in parallel with the capacitor 22, isarranged between the capacitor 22 and the drive circuit 57. The secondcapacitor 25 is smaller in capacitance than the capacitor 22. Thecapacitance of the capacitor 22 falls within a range from 1 to 15 μF,and is typically 10 μF or so. The capacitance of the second capacitor 25falls within a range from 0.05 to 0.5 μF, and is typically 0.1 μF. Withthe second capacitor 25 included, the supply of power to the IC (thedrive circuit 57) is continuously made to prevent the IC from being shutdown even if the switch 261 is momentarily disengaged due to vibrationsor shocks, thereby disconnecting the first capacitor 22 from the IC.

The brake control circuit 56 includes an indication error corrector unit200. Referring to FIG. 13, the indication error corrector unit 200includes a temperature sensor 201, such as a water-temperature sensor oran infrared temperature sensor, a voltage detector 202, such as acomparator for detecting a voltage across the capacitor 22, A/D(analog-to-digital) converters 203 and 204 for converting measurementvalues provided by the temperature sensor 201 and the voltage detector202, initial value setting means 205, which is a correction value setterfor setting, for the up/down counter 54, an initial value that accountsfor the output values of the converters 203 and 204, and a latch 207that latches the data output by the initial value setting means 205.

Referring to FIG. 14, the initial value setting means 205 includes aninitial value setting table 206 which sets the correspondence betweenthe output values of the temperature sensor 201 and the voltage detector202 (specifically, the output values of the A/D converters 203 and 204)and the initial value of the up/down counter 54. Each of theA/D-converters 203 and 204 gives a 5-bit output, namely an outputgraduated at 32 steps within a range from zero to 32. The initial valuesetting table 206 divides the outputs of the A/D converters 203 and 204at six gradations, and sets, in the up/down counter 54, an initial valuecorresponding to the output.

The initial value setting means 205 is connected to four data inputterminals (preset terminals) A-D of the up/down counter 54 via the latch207. The up/down counter 54 is supplied with the initial value byinputting a high-level signal or a low-level signal thereto inaccordance with the initial value set by the initial value setting table206.

The A/D converters 203 and 204, the initial value setting means 205, andthe latch 207 are designed to respond to a variation in the crownposition that takes place when the crown is pulled out or pushed in,namely, to a variation in a system reset signal (SR or a triggersignal).

In this embodiment, the generator 20 is controlled by the rotationcontroller 50 during the normal hand driving mode in the same way as inthe first embodiment. Furthermore, during the normal hand driving mode,i.e., with the crown placed in the zero step or the first step, thecurrent generated by the generator 20 charges the capacitor 22 throughthe rectifier circuit 21.

The voltage applied to the drive circuit 57 is equal to the voltage ofthe capacitor 22, namely, about 1.0 V as shown in FIG. 15.

Control during the time correction operation (hand setting operation) isperformed as discussed below.

When the crown is pulled out to the second step from the normal handdriving position for the hand setting operation, the switch 261 isopened in interlock with the pull of the crown (point A in FIG. 15). Atthe same time, the generator 20 stops. Since the second capacitor 25 isused in this embodiment, power is supplied by the second capacitor 25immediately subsequent to the stop of the generator 20. Because thecapacitance of the second capacitor 25 is small, the voltage thereacrossis rapidly reduced by the load of the drive circuit 57. When the voltageacross the second capacitor 25, namely, the voltage applied to the drivecircuit 57, drops below the voltage Vstop (approximately 0.6 V), thedrive circuit 57, namely, the oscillator circuit 51 stops.

With the switch 261 opened, almost no power of the capacitor 22 isconsumed, and the voltage of the capacitor 22 is maintained at a voltageof about 1.0 V.

When the crown is pushed in to the first step with the hand settingoperation completed, the switch 261 is closed (point B in FIG. 15).Electrical energy is then fed to the drive circuit 57 from the capacitor22, which has been maintained at a voltage of about 1.0 V, and theoscillator circuit 51 restarts operating.

Since the oscillator circuit 51 is supplied with a voltage as high as1.0 V as shown FIG. 16, time Tstart prior to the start of oscillation(corresponding to time T2 in the-conventional art shown in FIG. 26) issubstantially shortened to about 0.8 second (at an ambient temperatureof 25° C.). Since the time T1 needed prior to the voltage rise of thecapacitor 22 in the conventional art is eliminated, the time to theoperation of the oscillator circuit 51 subsequent to the hand settingoperation is substantially shortened.

When the oscillator circuit 51 operates, the control circuit 56 brakecontrols the generator 20. The initial value of the up/down counter 54in the control circuit 56 is set by the indication error corrector unit200.

Upon detecting the push of the crown, the A/D converters 203 and 204 inthe indication error corrector unit 200 outputs, to the initial valuesetting means 205, values corresponding to the measurement valuesprovided by the temperature sensor 201 and the voltage detector 202. Forinstance, as shown in FIG. 17, when the temperature measured by thetemperature sensor 201 falls within a range equal to or higher than 0°C. and lower than 4° C., the A/D converter 203 outputs a value “10”.When the temperature measured by the temperature sensor 201 falls withina range equal to or higher than 4° C. and lower than 8° C., the A/Dconverter 203 outputs a value “11”. In this way, the output of the A/Dconverter 203 changes in a stepwise fashion by temperature steps of4° C.Similarly, when the voltage measured by the voltage detector 202 fallswithin a range equal to or higher than 0.8 V and lower than 0.82 V, theA/D converter 204 outputs a value “10”. When the voltage measured by thevoltage detector 202 falls within a range equal to or higher than 0.82 Vand lower than 0.82 V, the A/D converter 204 outputs a value “11”. Inthis way, the output of the A/D converter 204 changes in a stepwisefashion by voltage steps of 0.02 V.

The initial value setting table 206 sets the initial value in accordancewith the oscillation start time Tstart, namely, the output values of theconverters 203 and 204. When the oscillation start time is short, thecontrol circuit 56 is driven quickly subsequent to the time correctionoperation, and a correction value of “0” may be acceptable. A standardinitial value (“11” ) may be set as the initial value of the up/downcounter 54. Specifically, as shown in FIG. 16, as the voltage of thecapacitor 22 is higher, and as temperature is higher, the oscillationstart time becomes shorter. When the values from the converters 203 and204 are large, an initial value of “11” is set.

When the oscillation start time is longer, more time is needed beforethe control circuit 56 is driven, and the time with no brake controlperformed on the generator 20 is prolonged. In this embodiment, themainspring 1 a outputs torque sufficient enough to allow the generator20 to rotate at a speed higher than the reference period of thegenerator 20. With a brake applied, the generator 20 is governed to thereference period. If the time with no brake control performed isprolonged, the rotation period of the generator 20 becomes shorter thanthe reference period. For this reason, the longer the time to the startof the oscillation, the stronger braking is applied to reduce therotational speed.

As in the first embodiment, strong brake control is performed with theoutput of the up/down counter 54 at “12” or larger, and weak brakecontrol is performed with the output of the up/down counter 54 at “11”or smaller. By setting a large initial value to the up/down counter 54(“15” at maximum), the time of the strong brake control is prolonged. Asthe voltage of the capacitor 22 is lower and as temperature is lower,the oscillation start time becomes longer. Therefore, as the outputvalues of the converters 203 and 204 become smaller, the initial valuesset become larger to “11”, “12”, “13”, “14”, and then to “15”.

Correction responsive to the time to the start of the oscillation of theoscillator circuit 51 is performed during the brake control by thecontrol circuit 56. As a result, the position of the hand is correctedto no slow nor fast time state (with zero indication error), and theindication error is eliminated.

When the generator 20 starts, reverting back to the normal operation,power from the generator 20 is fed to the drive circuit 57 through thecapacitor 22, and the generator 20 is continuously subjected to rotationcontrol.

This embodiment provides the following advantages.

(2-1) Since the timepiece includes the power supply control unit whichis composed of the switch 261 and is opened and closed in response tothe push and pull of the crown, namely, the time correction operation,no power is supplied to the rotation controller 50 from the capacitor(power supply circuit) 22 during the suspension of the generator 20 withthe crown pulled out, and the capacitor 22 maintains the terminalvoltage thereacross.

The capacitor 22 thus supplies power to the rotation controller 50immediately subsequent to the start of the generator 20 after the timecorrection operation. There occurs no time lag (time T1) until thevoltage of the power source for the drive circuit (drive IC) 57 rises tobe high enough to start oscillating, and the duration of time duringwhich the rotation control of the rotor is not performed is shortened,and the hand indication error is thus minimized.

(2-2) Since the switch 261 disconnects the capacitor 22 from the drivecircuit 57, the voltage across the capacitor 22 is maintained at arelatively high level (about 1.0 V, for instance) With this arrangement,the drive circuit 57 is supplied with a high voltage when the switch 261is closed. The time (Tstart) until the oscillation of the oscillatorcircuit 51 in the rotation controller 50 is thus shortened. The rotationcontroller 50 becomes operative more rapidly, reducing the indicationerror.

(2-3) Since the timepiece includes the control circuit 56 having theindication error corrector unit 200, an indication error, if any, iscorrected, and the indication error is reduced more, or almost removed.

(2-4) The indication error corrector unit 200 detects the voltageapplied to the capacitor 22, namely, the oscillator circuit 51, and thetemperature of the oscillator circuit 51, both affecting the oscillationstart time of the oscillator circuit 51, to set the correction value(the initial value at the up/down counter 54). The correction is thusprecisely performed, and the indication error is substantiallyminimized. Since the indication error is corrected by detecting not onlythe voltage applied to the oscillator circuit 51 but also temperaturethereof to adjust the correction values, the accuracy level of thecorrection values is improved, and the indication error is furthercorrected. The indication error is minimized, particularly when thetimepiece is used in cold areas with the temperature of the oscillatorcircuit 51 low, or when the timepiece is exposed to sunlight or is usedin hot areas with the temperature of the oscillator circuit 51 high.

(2-5) The indication error corrector unit 200 corrects the indicationerror by simply changing the initial value at the up/down counter 54.Compared with the arrangement in which the correction is made by addinga correction value to the output value of the up/down counter 54, theindication error is corrected using a simple arrangement, and costsinvolved are reduced.

(2-6) The switch 261, namely, the power supply control unit, is amechanically driven switch that operates in interlock with the pulloperation of the crown. The switch 261 thus has a simple construction,and the electronically controlled mechanical timepiece is manufacturedat low costs. It is sufficient if the switch 261 is merely added. Anincrease in the manufacturing cost is minimal, and the timepiece issupplied for a relatively low cost, compared with the conventional art.

(2-7) The second low-capacitance capacitor 25 is arranged, besides thecapacitor 22. Even when the switch 261 suffers from chattering, thecapacitor 25 feeds power to the drive circuit 57, and the drive circuit57 is prevented from being shut down as a result of chattering.

(2-8) Since an excessively large capacitance is not required of thecapacitor 22, the capacitor 22 is charged with the voltage thereofrapidly increasing from a state of no charge stored, within a shorttime.

Since a large generation capacity is not required of the generator 20,the sizes of the generator 20 and the mainspring la are made compact.This arrangement finds application in wristwatches, which are subject tothe limitation of area and thickness dimensions.

Next, a third embodiment of the present invention is now discussed,referring to FIG. 18 through FIG. 21. In this embodiment, componentsidentical or similar to those described in connection with the precedingembodiments are designated with the same reference numerals and thediscussion thereabout is omitted here.

FIG. 18 is a block diagram showing an electronically controlledmechanical timepiece, which is the electronically controlled timepieceof this invention.

The electronically controlled mechanical timepiece includes a mainspring1 a as a mechanical energy source, accelerating train wheels (series ofwheels) 7 as mechanical energy transmission means for transmittingtorque of the mainspring 1 a to a generator 20, and a hand 13, as a timedisplay unit for indicating time, connected to the accelerating trainwheels 7.

The generator 20 is driven by the mainspring 1 a via the acceleratingtrain wheels 7, and generates an electromotive force to supplyelectrical energy. The alternating-current output from the generator 20is rectified by a rectifier circuit 21, which has at least one of thefunctions of stepup and rectification, full-wave rectification,half-wave rectification, and transistor rectification, and is stepped upas required. The alternating-current voltage is then fed to a powersupply circuit 30 as a power source such as a capacitor to charge it.

The generator 20 is governed and controlled by the rotation controller50. The rotation controller 50 includes an oscillator circuit 51, arotor rotation detector circuit 53, and a brake control circuit 56, andthe construction thereof remains unchanged from that of the firstembodiment.

The oscillator circuit 51 generates an oscillation signal (32768 Hz)using a crystal oscillator 51A, i.e., a time standard source, and theoscillation signal is divided into a constant period through a frequencydivider and is output as a reference signal fs.

The rotation detector circuit 53 is composed of a wave shaping circuitconnected to the generator 20, and converts the alternating-currentoutput from the generator 20 into a rectangular wave, and outputs as arotation detection signal FG1 with noise removed therefrom.

The control circuit 56 compares the rotation detection signal FG1 withthe reference signal fs, thereby setting the amount of braking, andapplying a brake on the generator 20 to govern it.

Specifically, the rotation controller 50 includes a drive circuit 57composed of a drive IC for driving the oscillator circuit 51 as shown inFIG. 19. The drive circuit 57 is driven by power from a main capacitor31 (a main storage unit) forming the power supply circuit 30. The maincapacitor 31 ranges from 0.05 to 0.5 μF in capacitance, and is typicallya ceramic capacitor having a capacitance of about 0.2 μF. The maincapacitor 31 smoothes the current from the generator 20 to feed power tothe rotation controller 50.

An auxiliary capacitor (an auxiliary storage unit) 32, having acapacitance larger than that of the capacitor 31, is connected inparallel with the main capacitor 31. The auxiliary capacitor 32 rangesfrom 1 to 15 μF in capacitance, and typically has a capacitance of about10 μF.

A mechanically driven switch 361 is arranged between the capacitors 31and 32. In the electronically controlled mechanical timepiece of thisembodiment, the crown can be pulled out in three steps, wherein in azero step, the mainspring is tightened by turning the crown with thehands turning and the generator generating, and in a first step, acalendar is corrected by turning the crown with the hands turning andthe generator generating, and in a second step, time correction isperformed by turning the crown with the rotor stopping moving, the handsmotionless, and the generator not generating. The switch 361 is closedwith the crown placed in the first or zero step, and is opened with thecrown placed in the second step. In other words, the switch 361 is amechanically driven switch that operates in interlock with the timecorrection operation.

A switch 262 is connected to the drive circuit 57. The switch 262 is amechanically drive switch that operates in interlock with the switch361, and is used to input a crown position signal to the drive circuit57. Specifically, the switch 361 is closed with the crown placed in thezero or first position, and the switch 262 is connected to a zero andfirst step circuit in interlock with the switch 361. With the crownplaced in the second step, the switch 361 is opened, and the switch 262is connected to a second step circuit. Recognizing the signal from thethese circuits, the drive circuit 57 performs timepiece control, forinstance, performing normal hand driving control with the crown in thezero or first step, and setting or resetting a counter and systeminitialization with the crown in the second step.

A charge control circuit 35, composed of a diode 36 and a resistor 37 inparallel connection, is connected between the capacitors 31 and 32. Adiode having a smaller forward voltage Vf (0.2 V, for instance) ispreferable for the diode 36, and a Schottky barrier diode may be used.The diode 36 is configured so that the diode 36 is aligned opposite tothe direction of the charging current (from VDD to VSS) when thecapacitors 31 and 32 are charged by the rectifier circuit 21, namely, bythe generator 20, with the switch 361 closed, and is aligned with thedirection of the current flowing from the auxiliary capacitor 32 to themain capacitor 31.

The resistance of the resistor 37 is preferably large, and is 100 MΩ inthis embodiment.

The power supply circuit 30 is composed of the main capacitor 31, theauxiliary capacitor 32, the charge control circuit 35 (the diode 36 andthe resistor 37), and the switch 361.

In this embodiment, the normal hand driving is controlled in the samemanner as in the first embodiment. Specifically, during the normal handdriving mode, i.e., with the crown placed in the zero step or the firststep, the current generated by the generator 20 charges the capacitors31 and 32 through the rectifier circuit 21, because the switch 361 isclosed. Because of its small capacitance, the capacitor 31 tends to varyin voltage due to variations in the voltage of the generator 20 and theload of the drive circuit 57. But a large-capacitance auxiliarycapacitor 32 connected in parallel therewith backs up, therebymaintaining the voltage constant (approximately 1.0 V).

The voltage applied to the drive circuit 57 (the voltage of the maincapacitor 31) is maintained at the same level as that of the auxiliarycapacitor 32 as shown in FIG. 20.

Control during the time correction operation (hand setting operation) isperformed as follows.

When the crown is pulled out to the second step from the normal handdriving position for the hand setting operation, the switch 361 isopened in interlock with the pull of the crown (point A in FIG. 20).With the switch 361 opened, almost no power of the auxiliary capacitor32 is consumed, and the voltage of the capacitor 32 is maintained at avoltage of about 1.0 V.

During the hand setting operation, the generator 20 stops rotating,allowing no charging current to flow into the main capacitor 31. Thevoltage of the main capacitor 31 rapidly drops by the load of the drivecircuit 57. When the voltage of the main capacitor 31 becomes equal toor lower than the voltage Vstop (approximately 0.6 V), the drive circuit57 stops operating.

When the crown is pushed in to the first step after the hand settingoperation, the switch 361 is closed (point B in FIG. 20). A currentflows into the main capacitor 31 through the diode 36 from the auxiliarycapacitor 32 that is held at a voltage of approximately 1.0 V. Becauseof a small capacitance thereof, the main capacitor 31 reaches the samevoltage (1.0 V) as that of the auxiliary capacitor 32, and feedselectrical energy to the drive circuit 57, thereby causing theoscillator circuit 51 to start operating.

Since the oscillator circuit 51 is supplied with a high voltage of 1.0 Vas in the second embodiment as shown in FIG. 16, the time Tstart priorto the start of the oscillation (corresponding to the time T2 in theconventional art shown in FIG. 26) is shortened to be approximately 0.8second (at a temperature of about 20° C.). The duration of time from thepush of the crown (point B in FIG. 20) to the voltage of the maincapacitor 31 reaching 1.0 V is very short, and thereby the time theoscillator circuit 51 takes to start operating subsequent to the handsetting operation is substantially shortened.

When the hand setting operation takes 10 minutes or longer, or when thevoltage of the auxiliary capacitor 32 is zero V or in the vicinity ofzero V. (down to point C in FIG. 21) with the timepiece left unattendedfor a long period of time, the main capacitor 31 is also held at almostzero V.

When the switch 361 is closed after the hand setting operation, settingthe generator 20 operative (point C in FIG. 21), a major percentage ofthe current flows into the main capacitor 31 rather than into theauxiliary capacitor 32. Specifically, the diode 36 blocks the chargingcurrent of the generator 20 flowing to charge the auxiliary capacitor32, and the resistor 37 is as high as 100 MΩ. A major percentage of thegenerated current thus flows into the main capacitor 31 and almost nocurrent flows into the auxiliary capacitor 32. The generator 20 isdesigned to result in a current within a range from about 100 nA toseveral 10 μA with the capacitors 31 and 32 in the vicinity of zero V,and an extremely small current flowing through the resistor 37 isneglected.

The voltage of the main capacitor 31 rapidly rises with the majorpercentage of the generated current flowing thereinto. Along with this,the main capacitor 31 reaches the oscillation start voltage (Vstart) ofthe drive circuit 57 (IC) within a short time (approximately 1.5seconds, for instance) subsequent to the hand setting operation, and thecontrol starts. If no charge control circuit 35 were employed with thecurrent generated by the power supply circuit 30 flowing to bothcapacitors 31 and 32, the main capacitor 31 would take about 15 secondsto reach the oscillation start voltage of the drive circuit 57. In thisembodiment, the main capacitor 31 reaches the oscillation start voltagewithin one-tenth the time.

After the drive circuit 57 starts driving, a charging current graduallyflows into the auxiliary capacitor 32 through the resistor 37. After asufficiently long period of time has passed, the auxiliary capacitor 32reaches the same voltage as that of the main capacitor 31 (approximately1.0 V).

In the normal hand driving state, the auxiliary capacitor 32 serves as abackup for the main capacitor 31 in the event of voltage fluctuations,contributing to stabilizing the power source voltage and the systemoperation.

The oscillator circuit 51 substantially remains constant at a voltage ofapproximately 1.0 and the time Tstart to the oscillation is alsoconstant at about 0.8 second, when the auxiliary capacitor 32 holdscharge. The control circuit (the brake control circuit) 56 performsbrake control by applying a constant quantity correction correspondingto a predetermined value (approximately 0.8 second, for instance) tofurther reduce the indication error.

When the auxiliary capacitor 32 holds no charge, the voltage applied tothe oscillator circuit 51 gradually rises from about 0.7 V, and the timeTstart to the oscillation is substantially constant with about 1.5seconds (the time required for the main capacitor 31 to rise toVstart=0.7 V)+20 seconds (the time the oscillator circuit 51 takes tostart oscillating when a voltage of 0.7 V is applied thereto). Thecontrol circuit 56 performs brake control by applying a constantquantity correction corresponding to a predetermined value(approximately 21.5 seconds, for instance) to further reduce theindication error.

The selection between these correction values is determined by detectingthe voltage value applied to the control circuit 56 and the rotationperiod of the generator 20. Available as a method of setting thecorrection value is the method of counting time set in a timer or themethod of setting a timer in an analog fashion using a CR time constant.

When the generator 20 becomes operative, performing the normaloperation, power from the generator 20 is fed to the drive circuit 57via the main capacitor 31. The rotation control of the generator 20 isthus continuously performed.

This embodiment provides the following advantages.

(3-1) The charge control circuit, composed of passive elements such asthe diode 36 and the resistor 37, is employed to control the chargingand discharging of the main capacitor 31 and the auxiliary capacitor 32,and compared to the conventional art which employs the comparator, i.e.,an active element, power consumption is reduced.

With the comparator dispensed with, the ability of the generator 20 isreduced accordingly. Since a reduced energy supply from the mainspring 1a works, time of sustaining energy supply from the fully tightened stateof the mainspring 1 a is thus prolonged. With the size of the generator20 reduced, the component layout is facilitated within a timepiece bodyhaving limited space, and as a result, the timepiece itself is reducedin size. This arrangement finds application in wristwatches, which aresubject to the limitation of area and thickness dimensions.

(3-2) The timepiece includes the switch 361, which is opened and closedin response to the push and pull of the crown. When the generator 20 isstopped with the crown pulled out, the auxiliary capacitor 32 suppliesno power to the rotation controller 50, and maintains the terminalvoltage thereacross.

The auxiliary capacitor 32 feeds a current to the main capacitor 31,namely, the rotation controller 50 immediately subsequent to the startof the generator 20 after the hand setting operation. This embodiment isfree from a time lag of the conventional art, i.e., the time lag beforethe voltage of the power source of the drive circuit (the drive IC) 57rises high enough to start oscillation. The duration of time, duringwhich the rotation control of the rotor is not performed, is shortened,and the indication error is minimized. The present invention thusassures both the startup capability subsequent to the hand setting andthe accuracy of the hand setting at the same time.

When the auxiliary capacitor 32 charges the main capacitor 31, thecharging current flows through the diode 36, with a charging lossinvolved.

(3-3) Since the switch 361 disconnects the auxiliary capacitor 32 fromthe drive circuit 57, the auxiliary capacitor 32 is maintained at arelatively high voltage (about 1.0 V, for instance). When the switch 361is closed, the drive circuit 57 is supplied with the high voltage,shortening the time (Tstart) until the oscillator circuit 51 in therotation controller 50 starts oscillating. The rotation controller 50 iseven more rapidly operated, reducing the indication error.

(3-4) A small-capacitance main capacitor 31 is employed, and the chargecontrol circuit 35 is arranged to allow more charging current from thegenerator 20 to flow into the main capacitor 31, when no charge isstored in the capacitors 31 and 32, for instance, after the timepiecehas been left unattended for a long period of time. The time, the maincapacitor 31 takes to reach the voltage capable of driving the drivecircuit 57 from a zero-volt state thereof, is shortened approximatelyone-tenth the time required when no charge control circuit 35 isemployed. After being left unattended for a long period of time, thepresent invention thus assures both the startup capability subsequent tothe hand setting and the accuracy of the hand setting at the same time.

If the drive circuit 57 is not driven after the hand setting, and nobrake is applied on the hand driving at all in a free running state, thesecond hand moves fast, and the user may have anxiety about and loseconfidence in the timepiece. In this embodiment, the drive circuit 57resumes the driving operation within a short time. There is almost notime during which the second hand moves fast, and the user's confidencein the timepiece is thus maintained.

(3-5) The main capacitor 31 is directly connected to the drive circuit57, not by way of the mechanically driven switch 361. Even if themechanically driven switch 361 chatters, the main capacitor 31continuously feeds power to the drive circuit 57, thereby preventing thedrive circuit 57 from being shut down as a result of chattering.

(3-6) Since the auxiliary capacitor 32, having a capacitance larger thanthat of the main capacitor 31, is connected in parallel with the maincapacitor 31, the auxiliary capacitor 32 may back up the main capacitor31 in the event of voltage fluctuations, contributing to stabilizing thepower source voltage and the system operation.

(3-7) Although the time until the drive circuit 57 starts drivingsubsequent to the hand setting operation becomes different depending onwhether the auxiliary capacitor 32 holds charge, the time is controlledto a substantially constant. The indication error is corrected byperforming a constant quantity correction using a predetermined value.The indication error is thus minimized, and the accuracy of the handsetting is even further improved.

(3-8) The charge control circuit 35 is composed of low-cost elements,such as the diode 36 and the resistor 37. Compared to the arrangementusing a comparator, the manufacturing costs are reduced, and a low-costtimepiece is thus supplied.

(3-9) The control of the charging current to the capacitors 31 and 32through the charge control circuit 35 is performed by selecting a properresistance for the resistor 37. Depending on the type of a timepiece, aproper resistance value may be selected.

(3-10) The indication error is corrected through the constant quantitycorrection control using a predetermined value. The construction of theindication error corrector unit (control circuit) 56 is thus simplifiedand the cost thereof is accordingly reduced.

A fourth embodiment of the present invention is now discussed, referringto FIG. 22.

In this embodiment, the charge control circuit 35 is constructed of onlya diode 38 having a reverse leakage current. In this case, when thegenerator 20 charges the capacitors 31 and 32, the charging current tothe auxiliary capacitor 32 becomes extremely small because the chargingcurrent is the reverse leakage current of the diode 38 only. A majorpercentage of the charging current flows into the main capacitor 31. Inthe same way as in the preceding embodiment, the main capacitor 31rapidly rises in voltage, thereby shifting the drive circuit 57 into acontrol state within a short period of time.

When the auxiliary capacitor 32 holds charge, the auxiliary capacitor 32feeds a current to the main capacitor 31 through the diode 38. The drivecircuit 57 is rapidly driven, with a small current loss involved.

Besides the advantages (3-1) through (3-9) of the third embodiment, thefourth embodiment enjoys a cost reduction, because the diode 38 only isused for the charge control circuit 35.

A fifth embodiment of the present invention is now discussed, referringto FIGS. 23 and 24. This embodiment includes the indication errorcorrector unit 200 in the second embodiment in the control circuit 56 inthe third embodiment.

When the switch 361 is closed with the auxiliary capacitor 32 holdingcharge after the time correction operation, the auxiliary capacitor 32charges the main capacitor 31 by feeding a current to the main capacitor31 through the diode 36, thereby very quickly driving the drive circuit57. In the same way as in the second embodiment, when the drive circuit57 is driven, the indication error corrector unit 200 performs brakecontrol on the generator 20 taking into account the correction valuesthat account for the oscillation start time and temperature. Theindication error is thus removed.

When the switch 361 is closed with the auxiliary capacitor 32 holding nocharge, a major percentage of the charging current flows into the maincapacitor 31 by way of the charge control circuit 35. In the same way asin the preceding embodiment, the main capacitor 31 rapidly rises involtage, shifting the drive circuit 57 into a control state within ashort period of time. In this case, as well, the indication error isremoved, because the indication error corrector unit 200 corrects brakecontrol for the generator 20.

This embodiment enjoys the advantages (2-3) through (2-5) provided bythe use of the indication error corrector unit 200 in the secondembodiment and advantages (3-1) through (3-9) in the third embodiment.

The present invention is not limited to the above embodiments, andchanges and modifications, within which the object of the presentinvention is achieved, fall within the scope of the present invention.

In the first embodiment, for instance, the power source switch (thepower cutoff switch 162) is arranged in the power source VSS.Alternatively, the power source switch may be arranged on the powersource VDD or may be arranged on each of the power sources VDD and VSS.It is important that the power source switch cuts off the supply ofelectrical energy to the analog circuit 160 to reduce the powerconsumption, and the position of and the construction of the powersource switch may be arbitrarily set.

The power source switch (the power cutoff switch 162) is not limited tothe one that is driven by a signal from the crown detector circuit 180.The power source switch may be a mechanically driven switch thatoperates in interlock with the operation of the crown. Alternatively,the power source switch may be opened and closed in interlock with thestop and activation of the generator 20 or the train wheels. It isimportant that the power source switch be opened and closed in interlockwith the hand setting operation.

The clock input limiting means (the clock cutoff gate 171) is notlimited to the AND gate in the first embodiment. Alternatively, theclock input limiting means may be a switch that connects or disconnectsthe signal line between the oscillator circuit 51 and the logic circuit170. It is important that the clock input limiting means block the clockinput to the logic circuit 170.

Unlike the first embodiment, the selection switch 186 in the crowndetector circuit 180 is configured so that the second signal line 184 isconnected to the zero and first steps and that the first signal line 183is connected to the second step. In this case, the output signal of thecrown detector circuit 180 is inverted, and the power cutoff switch 162and the clock cutoff gate 171 need to be configured in accordance withthe output signal.

The signal input line 185 of the crown is connected to the power sourceVDD in the first embodiment. Alternatively, the signal input line 185 isconnected to the power source VSS side. In this case, the crown detectorcircuit 180 is configured so that the crown position may be detected bythe closing of the switch 186 connected to the power source VSS.

The switch 186 may be configured to continuously connect to the signalline 183 or 184 with the crown placed in each step. With the twoinverters 181 and 182 thereof, the crown detector circuit 180 sustainsthe signal input from the switch 186. The switch 186 may beinstantaneously put into contact with one of the signal lines 183 and184 when the crown is switched, and may be held in an intermediateposition remaining unconnected to any of the signal lines 183 and 184until the crown is switched next.

The external control member detector circuit (the crown detector circuit180) is not limited to the construction of the preceding embodiments.The external control member detector circuit may be a conventional crowndetector circuit shown in FIG. 28. The use of the crown detector circuit180 of the preceding embodiments further reduces power consumption.

The external control member for switching between the hand setting modeand the normal hand driving mode is not limited to the crown, and may bea dedicated button or lever. The external control member may be amechanically driven one or an electrical one. A suitable control membermay be selected. Furthermore, the external control member detectorcircuit is not limited to the one for detecting the voltage as in thepreceding embodiments. The external control member detector circuit maydirectly detect the position of the external control member using alever or a push button, which moves along with the external controlmember. In accordance with the type of the external control member, theexternal control member circuit may be appropriately set up.

The power supply circuit for driving the logic circuit is not limited tothe constant voltage regulator 161, and any circuit capable of drivingthe logic circuit is acceptable.

In the first embodiment, the registers of pre_RYZ (for the previouscrown position data) and now_RYZ (for the present crown position data)are arranged to determine whether there is any change in the crownposition (step S4 in FIG. 8). Alternatively, only now_RYZ (for thepresent crown position data) may be arranged, and steps S1, S3, S4, andS5 in FIG. 8 may be eliminated to proceed from the detection of thecrown position (S2) directly to the determination of the crown position(S6). In the first embodiment, a change in the crown position isdetermined, and only when there is any change, the power supply controlprocess (S7 through S12) is performed for efficient control.

The first embodiment of the present invention may be implemented in aself-winding generator timepiece, a solar-cell charging timepiece, or abattery driven timepiece, other than the electronically controlledmechanical timepiece. In these timepieces, the power consumption duringthe hand setting operation is reduced. The driving time is prolonged,while the indication error is eliminated because the oscillator circuitcontinuously works.

In the second and fifth embodiments, the indication error corrector unit200 in the control circuit 56 detects the voltage applied to thecapacitor 22 and the temperature thereof, and corrects the indicationerror by the correction value that accounts for the detected voltage andtemperature. As in the third embodiment, the indication error may becorrected by a constant quantity correction corresponding to thepredetermined value.

The correction of the indication error may be performed by only thevoltage of the capacitor 22, or in response to the rotation period ofthe generator 20. For instance, the voltage of the capacitor 22 isdetected to perform correction in accordance with the correction valueresponsive to the voltage value. When the voltage held by the capacitor22 is as high as 1.2 V, the correction value may be “0”, and when thevoltage held by the capacitor 22 is as low as 0.8 V, the correctionvalue may be minus 1.0 second (−1.0 second).

The charge voltage to the capacitor 22 is typically proportional to thetorque of the mainspring 1 a applied to the generator 20, and the torquedetermines the rotation speed of the hand. A check is made to determinethe correspondence between the voltage value of the capacitor 22 and thefast/slow position of the hand at the start time at which the brakecontrol starts with the oscillator circuit 51 driven by the voltagevalue of the capacitor 22. The correspondence table between the voltagevalue and the hand indication error may be stored in the control circuit56 or other circuit.

For instance, when the capacitor 22 is at 1.2 V, the hand position isfree from a fast/slow error (no indication error) at the start time atwhich the brake control starts (approximately 0.2 second later). Bysetting the correction value to zero, the indication error is almostremoved.

When the capacitor 22 is at 0.8 V, the hand has been driven (moved) by 9seconds by the start of the brake control (the time to the oscillation,and approximately 8 seconds). By setting a correction of the differenceof 1 second in the brake control, the indication error is almostremoved.

The indication error corrector unit 200 is not limited to thearrangement in which the initial value is set in the up/down counter 54in the second embodiment. For instance, the output value LBS of theup/down counter 54 may be directly adjusted for correction. Anotherbrake circuit for correction, different from the normally used brakecircuit 120, may be arranged. It is important that the timepiece beconstructed to correct the indication error thereof.

The specific construction of the switch 261, namely, the power supplycontrol unit, may be properly arranged. The power supply control unit isnot limited to the mechanically driven switch, and may be an electricalswitch. To reliably cut off the supply of power, the mechanically drivenswitch is preferable. Even when the electrical switch is employed,merely a leakage current (as large as approximately 1 nA) of a silicondiode forming the electrical switch is discharged, and the switch cutoffeffect thereof is almost identical to that of the mechanically drivenswitch. The electrical switch practically presents no problems.

The switch 261 is not limited to the switch which is opened and closedin interlock with the operation of the crown (the time correctionoperation). Alternatively, the switch 261 may be a switch which isopened and closed in interlock with the stop and activation of thegenerator 20 or the train wheels. Interlocked with the operation of thecrown, the switch 261 advantageously has a simple and low-costconstruction.

In the second embodiment, the use of the second capacitor 25 is not arequirement. As shown in FIG. 25, the second capacitor 25 is dispensedwith, and the capacitor 22 only may be used.

The charge control circuit 35 is not limited to the ones in the thirdand fourth embodiments. The charge control circuit 35 may be constructedof a one-way element and a resistor. A diode having no reverse leakagecurrent may be used for the one-way element. In this case, the one-wayelement works like the diode 36 in the third embodiment, and theresistor works like the resistor 37, and the advantages (3-1) through(3-9) of the third embodiment are equally enjoyed.

An active element, such as a comparator, may be used for the chargecontrol circuit 35. The charge control circuit 35 allows more chargingcurrent from the generator 20 to the main capacitor 31, and lesscharging current to flow to the auxiliary capacitor 32. When the voltageof the auxiliary capacitor 32 is higher than that of the main capacitor31, the auxiliary capacitor 32 supplies a current to the main capacitor31. To this end, the charge control circuit 35 is configured to adjustthe charging current of the main storage unit and the auxiliary storageunit, and the direction and magnitude of the current flowing between themain storage unit and the auxiliary storage unit. The charge controlcircuit 35 constructed of passive elements only is preferable in view ofa reduction in power consumption.

The control circuit 56 in the third and fourth embodiments corrects theindication error by the constant quantity correction corresponding to apredetermined constant value. Alternatively, as in the secondembodiment, the indication error corrector unit 200 may be arranged toperform the correction in response to the voltage value, temperature,and the rotation period of the generator 20. Furthermore, in the thirdand fourth embodiments, the use of the indication error corrector unit200 is not a requirement. In this case, when temperature is extremelylow, or when the voltage of the auxiliary capacitor 32 drops, theoscillator circuit 51 takes time to start oscillating, and an indicationerror is accordingly created. However, the indication error is removedin the course of the hand driving control. Specifically, with theindication error corrector unit 200 incorporated, the time required toremove the indication error is substantially shortened subsequent to thetime correction operation. On the other hand, when the indication errorcorrector unit 200 is not arranged, the time required to remove theindication error is mildly prolonged. But this degree of timeprolongation is not problematic in practice, because the indicationerror is removed within 1 to several minutes. When the voltage of theauxiliary capacitor 32 is assured with temperature not substantiallylow, the time the oscillator circuit takes to start oscillating istypically short, and the indication error is removed without the needfor the indication error corrector unit 200.

The specific construction of the switch 361 may be appropriately set up.The switch 361 is not limited to the one which is opened and closed ininterlock with the operation of the crown. The switch 361 may be openedand closed in interlock with the stop and activation of the generator 20or the train wheels. However, if the switch 361 is interlocked with theoperation of the crown, it will be manufactured simply and for a lowcost.

The types, the reverse leakage currents, and the resistances of thediodes 36 and 38, and the resistor 37 may be appropriately determined indesign. Particular attention needs to be given to the resistance of theresistor 37 and the reverse leakage current of the diode 38, becausethese affect the magnitude of the charging current of the auxiliarycapacitor 32.

In the first embodiment, the indication error corrector unit 200 may beincluded in the control circuit 56 as in the second embodiment. Thepower supply circuit 30 in the third and fourth embodiments may bearranged as a power supply circuit in the first embodiment. In the firstembodiment, even when the generator 20 stops during the time correctionoperation, the oscillator circuit 51 continuously remains operative frompower from the capacitor 22. The timepiece of the first embodiment isfree from the indication error at the shifting back from the timecorrection operation. However, an indication error takes place when thecapacitor 22 is discharged to the extent that the oscillator circuit 51becomes inoperative if a time correction operation takes time or if thetimepiece has been left unattended for a long period of time. With thepower supply circuit 30 incorporated, the oscillator circuit 51 quicklyrestarts, reducing the indication error at the moment the generator 20becomes operative, even when the capacitor 22 is discharged. With theindication error corrector unit 200 further incorporated, the indicationerror at the restart of the oscillator circuit 51 is even more reduced.

In each of the above embodiments, two types of chopping signals CH3having different duty factors are input to the switch 121 for brakecontrol. The brake control may be performed by inputting an inverted LBSsignal, rather than using the chopping signal. In each of the aboveembodiments, the brake control is performed by making a closed loopbetween the terminals MG1 and MG2 in the generator 20 to carry out ashort-circuit brake. Alternatively, the brake control may be performedby connecting a variable resistor to the generator 20 to vary a currentflowing through the coil of the generator 20. Consequently, the specificconstruction of the brake control circuit 56 is not limited to thearrangement shown in FIG. 2, and may be appropriately set up.

The mechanical energy source for driving the generator 20 is not limitedto the mainspring 1 a, and may be a rubber member, a spring, a weight,or a fluid such as compressed air. An appropriate mechanical energysource may be selected in accordance with an apparatus in which thepresent invention is implemented. Means for feeding mechanical energy tothe mechanical energy source may be manual winding, an oscillatingweight, potential energy, pressure variations, wind force, wave power,hydraulic power, or temperature differences.

Mechanical energy transmission means for transmitting mechanical energyfrom the mechanical energy source such as a mainspring to the generatoris not limited to the train wheels 7 (gears), and may be a frictionalwheel, a belt (such as a timing belt), a pulley, a chain, a sprocketwheel, a rack and pinion, or a cam. The mechanical energy transmissionmeans is appropriately set up in accordance with the type of theelectronically controlled timepiece in which the present invention isimplemented.

The generator is not limited to the one which generates power throughelectromagnetic conversion by rotating the rotor. Alternatively, thegenerator may be a generator of a different type, such as apiezoelectric generator which adds pressure to a piezoelectric element.

The time display unit is not limited to the hand 13, and may be a disk,a ring-shaped member or a sector member. The time display unit may be adigital display unit employing a liquid-crystal display panel.

Industrial Applicability

As discussed above, the time indication error is reduced in theelectronically controlled timepiece of the present invention, the powersupply control method for the electronically controlled timepiece, andthe time correction method for the electronically controlled timepiece.

In the electronically controlled timepiece and the power supply controlmethod therefor in accordance with a first invention, the use of thepower source switch and the clock input limiting means reduces the powerconsumption involved in the time correction operation, (the hand settingoperation). Since the oscillator circuit continuously remains operativeduring the time correction operation, a time indication error at thetime of shifting back from the time correction operation is eliminated.

In the electronically controlled timepiece and the time correctionmethod therefor in accordance with a second invention, increasing thecapacitance of the capacitor and the size of the mechanical energysource is not required. The electronically controlled timepiece is thusminiaturized with costs thereof reduced. Even when the time correctionoperation (the hand setting operation) takes time, the time theoscillator circuit takes to start oscillating is shortened. Since theindication error corrector unit corrects the indication error, theindication error of the hand subsequent to the time correction operationis minimized.

In the electronically controlled timepiece and the power supply controlmethod therefor in accordance with a third invention, the rotationcontroller is quickly driven to reduce an error in the time control whenthe generator starts generating. Furthermore, the passive elements, suchas a diode and a resistor, are used for the charge control circuit, thepower consumption involved therein and the power generating capacity maybe small, compared with the arrangement in which an active element, suchas a comparator, is employed.

What is claimed is:
 1. An electronically controlled timepiececomprising: a power source; a logic circuit; an analog circuit driven bysaid power source, said analog circuit including a power supply circuitarranged in the analog circuit and having an output for driving saidlogic circuit; an oscillator circuit driven by the output of said powersupply circuit for the logic circuit; a power source switch forsuspending the supply of electrical energy from said power source tosaid analog circuit except said power supply circuit for said logiccircuit during a time correction operation of the electronicallycontrolled timepiece; and clock input limiter for suspending a clockinput from said oscillator circuit to said logic circuit during saidtime correction operation.
 2. An electronically controlled timepieceaccording to claim 1, wherein the power supply circuit for the logiccircuit comprises a constant voltage regulator.
 3. An electronicallycontrolled timepiece according to of claim 1, comprising logic circuitinitializing means for initializing the internal status of the logiccircuit during the time correction operation.
 4. An electronicallycontrolled timepiece according to claim 1, comprising: a mechanicalenergy source, a generator which is driven by the mechanical energysource, and generates an electromotive force, thereby supplyingelectrical energy, and a rotation controller, driven by the electricalenergy, for controlling the rotation period of the generator.
 5. A powersupply control method for an electronically controlled timepiececomprising a power source, an analog circuit driven by the power source,said analog circuit including a power supply circuit arranged in theanalog circuit for a logic circuit, the logic circuit being driven bythe output of the power supply circuit therefor, and an oscillatorcircuit driven by the output of the power supply circuit for the logiccircuit, the power supply control method comprising: the step ofsuspending the supply of electrical energy from the power source to theanalog circuit except the power supply circuit for the logic circuitduring a time correction operation of the electronically controlledtimepiece, and the step of suspending a clock input from the oscillatorcircuit to the logic circuit during the time correction operation.
 6. Apower supply control method for an electronically controlled timepieceaccording to claim 5, comprising the step of initializing the internalstatus of the logic circuit during the time correction operation of theelectronically controlled timepiece.
 7. An electronically controlledtimepiece comprising: a mechanical energy source; a generator driven bythe mechanical energy source, said generator being effective foroutputting electrical energy; a storage unit for storing electricalenergy output by the generator; a rotation controller driven byelectrical energy supplied by the storage unit, said rotation controllerbeing effective for controlling the rotation period of the generator; apower supply control unit for suspending the supply of electrical energyfrom the storage unit to the rotation controller while the generatorstops the operation thereof in response to a time correction operation,and an indication error corrector unit for correcting an error in timeindication until the rotation controller resumes a normal operationwherein the power supply control unit restarts the supply of electricalenergy from the storage unit to the rotation controller in response tothe activation of the generator.
 8. An electronically controlledtimepiece according to claim 7, wherein the indication error correctorunit is designed to perform a constant quantity correction correspondingto a predetermined value.
 9. An electronically controlled timepieceaccording to claim 7, wherein the indication error corrector unit sets acorrection value in accordance with a voltage of the storage unit. 10.An electronically controlled timepiece according to claims 7, whereinthe indication error corrector unit adjusts a correction value inresponse to detected temperature.
 11. An electronically controlledtimepiece according to claim 7, wherein the indication error correctorunit comprises: a temperature sensor, a voltage detector for measuring avoltage of the storage unit, and a correction value setter for setting acorrection value based on values detected by the temperature sensor andthe voltage detector.
 12. An electronically controlled timepieceaccording to one of claim 7, wherein the power supply control unitcomprises a switch which is connected in series with the storage unitand is closed while the generator is running, and is opened while thegenerator is not running.
 13. An electronically controlled timepieceaccording to claim 12, wherein the switch is a mechanically drivenswitch.
 14. An electronically controlled timepiece according to claim13, wherein the switch is a mechanically driven switch that is openedwhen a crown remains pulled out during a time correction mode, and isclosed when the crown is pushed in during a normal mode.
 15. Anelectronically controlled timepiece according to claim 7, comprising asecond storage unit connected in parallel with the storage unit.
 16. Atime correction method for an electronically controlled timepieceincluding a mechanical energy source, a generator driven by themechanical energy source, said generator being effective for outputtingelectrical energy, a storage unit for storing electrical energy outputby the generator, and a rotation controller driven by electrical energysupplied by the storage unit, said rotation controller being effectivefor controlling the rotation period of the generator, said timecorrection method comprising: the step of suspending the supply ofelectrical energy from the storage unit to the rotation controllerduring a time correction operation of the electronically controlledtimepiece, and the step of correcting an error in time indication untilthe rotation controller resumes a normal operation when the supply ofelectrical energy from the storage unit to the rotation controller isrestarted at the end of the time correction operation.
 17. A timecorrection method for an electronically controlled timepiece accordingto claim 16, wherein an indication error is corrected by a constantquantity correction corresponding to a predetermined value at the end ofthe time correction operation.
 18. A time correction method for anelectronically controlled timepiece according to claim 16, wherein anindication error is corrected by a correction value set in response to avoltage of the storage unit, at the end of the time correctionoperation.
 19. A time correction method for an electronically controlledtimepiece according to one of claim 16, wherein temperature is detectedat the end of the time correction operation, and the correction value isadjusted in response to the detected temperature.
 20. A timepiececomprising: a power supply including: a first power rail and a secondpower rail; a power generator selectively placed in an active mode inwhich power is supplied to said first and second power rails and in aninactive mode in which power is not supplied to said first and secondpower rails; a first power storage device for receiving power from saidpower generator through said first and second power rails; a first powerload coupled to said first power storage device; a second power loadcoupled to said first power storage device, said second power load beinga voltage regulator having an output coupled to a third power rail toprovide a regulated output voltage on said third power rail; a pulsegenerator coupled to said third power rail for receiving said regulatedoutput voltage, said pulse generator having a clock output for producinga clocking signal when the voltage of said third power rail is above aminimum active voltage level; a digital circuit coupled to said thirdpower rail for receiving said regulated output voltage and having aclock input selectively coupled to said clock output; wherein said firstpower load is decoupled from said first power storage device and saidclock input is decoupled from said clock output when said powergenerator is in said inactive mode.
 21. The timepiece of claim 20wherein said first power load is an analog circuit.
 22. The timepiece ofclaim 20 wherein said pulse generator and said digital circuit aremaintained coupled to said third power rail during both active andinactive modes of said power generator.
 23. The timepiece of claim 20wherein said pulse generator includes at least an oscillator.
 24. Thetimepiece of claim 23, wherein said oscillator is substantially the onlyload on said third power rail drawing power from said third power railduring said inactive mode.
 25. The timepiece of claim 20 further havinga logic gate to mask the output of said clock output from said clockinput during said inactive mode whereby said clock input is decoupledfrom said clock output.
 26. The timepiece of claim 20, wherein saiddigital circuit includes a control output node for producing a periodicerror correction signal for regulating the generation of power by saidpower generator when said power generator is in said active mode and forproducing no error correction signal when said power generator is saidinactive mode.
 27. The timepiece of claim 26, wherein the initial amountof power regulation applied to said power generator at a transition fromsaid inactive mode to said active mode is larger when the voltage ofsaid third power rail falls below said minimum active voltage levelduring said inactive mode than when the voltage of said third power railremains above said minimum active voltage level during said inactivemode.
 28. The timepiece of claim 26, wherein the initial amount of powerregulation applied to said power generator at a transition from saidinactive mode to said active mode is dependent on the voltage of saidfirst power storage device.
 29. The timepiece of claim 28, wherein theinitial amount of power regulation is inversely proportional to thevoltage of said first power storage device.
 30. The timepiece of claim28, wherein the initial amount of power regulation applied to said powergenerator at a transition from said inactive mode to said active mode isfurther dependent on temperature.
 31. The timepiece of claim 30, whereinthe initial amount of power regulation applied to said power generatorat a transition from said inactive mode to said active mode is inverselyproportional to temperature.
 32. The timepiece of claim 30, wherein saiddigital circuit further includes: a temperature sensor to produce adigital representation of the temperature; a voltage detector coupled tosaid first power storage device to produce a digital representation ofobserved voltage across said first power storage device.
 33. Thetimepiece of claim 26, wherein the initial amount of power regulationapplied to said power generator at a transition from said inactive modeto said active mode is dependent on initial conditions of said digitalcircuit following a transition from said inactive mode to said activemode of said power generator.
 34. The timepiece of claim 33, whereinsaid initial conditions are loaded as a numerical value into saiddigital circuit following said inactive mode.
 35. The timepiece of claim34, wherein said numerical value is fixed such that said digital circuithas the same initial conditions at every transition from said inactivemode to said active mode.
 36. The timepiece of claim 34, wherein thenumerical value loaded into said digital circuit is a firstpredetermined value when the voltage of said third power rail remainsabove said minimum active voltage value during said inactive mode and isa second predetermined value when the voltage of said third power railfalls below said minimum active voltage value during said inactive mode.37. The timepiece of claim 36, wherein said second predetermined valueis greater than said first predetermined value.
 38. The timepiece ofclaim 34, wherein the numerical value loaded into said digital circuitis selected from a table of predetermined values.
 39. The timepiece ofclaim 38, wherein the numerical value to be loaded into said digitalcircuit is selected from among said predetermined values in said tablein accordance with a measured voltage across said first power storagedevice and a measured temperature.
 40. The timepiece of claim 39,wherein said digital circuit further includes: a temperature sensor tomeasure said temperature and produce a digital representation of themeasured temperature; a voltage detector coupled to said first powerstorage device to produce a digital representation of said measuredvoltage across said first power storage device.
 41. The timepiece ofclaim 20, wherein the duty cycle of said error correction signal isdependent on initial conditions of said digital circuit following atransition from said inactive mode to said active mode of said powergenerator.
 42. The timepiece of claim 26, wherein the initial duty cycleof said error correction signal at a transition from said inactive modeto said active mode is larger when the voltage of said third power railfalls below said minimum active voltage level during said inactive modethan when the voltage of said third power rail remains above saidminimum active voltage level during said inactive mode.
 43. Thetimepiece of claim 26, wherein at a transition from said inactive modeto said active mode, the initial duty cycle of said error correctionsignal is assigned a first predetermined value if the voltage of saidthird power rail falls below said minimum active voltage level duringsaid inactive mode and assigned a second predetermined value otherwise.44. The timepiece of claim 26, wherein at a transition from saidinactive mode to said active mode, the initial duty cycle of said errorcorrection signal is determined by an assigned value dependent on thevoltage of said first power storage device.
 45. The timepiece of claim44, wherein said assigned value is further dependent on temperature. 46.The timepiece of claim 26, wherein said error correction signal iseffective for regulating the generation of power by said power generatorwhen said power generator is in said active mode.
 47. The timepiece ofclaim 26, wherein said control output node is coupled to a control inputnode of said power generator and is effective for retarding thegeneration of power by said generator in accordance with said errorcorrection signal.
 48. The timepiece of claim 26, wherein said powergenerator includes an AC power generating circuit coupled to a voltagerectifier, and said digital circuit includes at least an errorcorrection circuit for generating said error correction signal, saiderror correction circuit being responsive to the frequency of said ACpower generating circuit.
 49. The timepiece of claim 48, wherein saidpower generator uses a multiple of said clocking signal to obtain ameasure of the frequency of said AC power generating circuit, the dutycycle of said error correction signal being adjusted to be proportionalto said measure of the frequency of said AC power generating circuit.50. The timepiece of claim 49, wherein said error correction signal iseffective for reducing the frequency of said AC power generating circuitwhereby a feedback system is established.
 51. The timepiece of claim 50,wherein said error correction circuit includes a counter for determiningthe application of said error correction signal, said counter beingreset to an initial count value at a transition from said inactive modeto said active mode.
 52. The timepiece of claim 51, wherein said counteris reset to the same predetermined count value at every transition fromsaid inactive mode to said active mode.
 53. The timepiece of claim 51,wherein said counter is reset to a first predetermined count value inresponse to the voltage of said third power rail remaining above saidminimum active voltage during said inactive mode, and is reset to asecond predetermined count value in response to the voltage of saidthird power rail falling below said minimum active voltage during saidinactive mode.
 54. The timepiece of claim 53, wherein said secondpredetermined count value is greater than said first predetermined countvalue.
 55. The timepiece of claim 53, wherein said second predeterminedcount value is selected from a table of available count values.
 56. Thetimepiece of claim 55, wherein a target count value from among saidtable of available count values is selected as said second predeterminedcount value in accordance with the voltage across said first powerstorage device.
 57. The timepiece of claim 55, wherein a target countvalue from among said table of available count values is selected assaid second predetermined count value in accordance with the temperatureof said pulse generator.
 58. The timepiece of claim 20, further having asecond power storage device coupled between said first and second powerrails, said first power storage device being decoupled from at least oneof said first and second power rails during said inactive mode and beingre-coupled to said first and second power rails in response to saidactive mode.
 59. The timepiece of claim 58, wherein said second powerstorage device remains coupled to said first and second power railsduring both of said active mode and inactive mode.
 60. The timepiece ofclaim 58, wherein said first power storage device has a greater powerstorage capacity than said second power storage device.
 61. Thetimepiece of claim 60, wherein said first and second power storagedevices are respective first and second capacitors.